Math Questions

A scientist models the number of grams of a radioactive substance with the expression 15.(1/2)^d/5, where d is the number of days since the sample was measured. 1. After how many days has half of the substance disappeared through radioactive decay? Explain your reasoning. 2. After 20 days, will there be more or less than 1 gram of the substance left? Explain your reasoning.

Marvin lives in Stormwind City and works as an engineer in the city of Ironforge. In the morning, he has 3 transportation options (teleport, ride a dragon, or walk) to work, and in the evening he has the same 3 choices for his trip home. If Marvin randomly chooses his method of travel in the morning and in the evening, what is the probability that he teleports at least once per day?

A random study reported that 70% of very-low-birth-weight babies graduate from high school by age 20. If 180 very-low-birth-weight babies are followed through high school, how many would you expect to graduate from tgh schod

Kaleb has $850 saved for college. Kaleb expects the total cost of his first year to be $8,990. He has $850 in his savings account. He will receive grants and scholarships that total $1,445. Kaleb plans to save $210 every month. At this rate, how many months will Kaleb need to save until he has enough money to pay for the net price of his first year of college? A 31 months C 36 months B 32 months D 46 months

A bag contains 5 blue marbles, 4 red marbles, and 3 orange marbles. Mrs. Cox picks one without looking, replaces it and picks another one. What is the probability that she picks two that are not orange?

The U-Drive Rent-A-Truck company plans to spend $13 million on 320 new vehicles. Each commercial van will cost 535 000, each small truck $30,000, and each large truck $80,000 Past experience shows that they need tance as many varsas malucks How many of each type of vehicle can they buy? They can buy vans.small trucks, and large trucks

What is the length of one side of a square whose area is 100 square meters? What is the perimeter of a rectangle whose base has a length of 15 inches and whose diagonal measure 17 inches?

Write the standard form of the equation of a circle with radius 8 and center (-9,1)

Spongebob, Patrick, and Mr. Krabs are investing a total of $70,000 in the Krusty Krab at a ratio of 12:7:16. How much money did each of them invest? Spongebob: Patrick: Mr. Krabs:

The beachfront path was 4,848 feet long. A tropical storm caused waves that washed away 3,383 feet from the end. How long was the path after the storm? 1,475 feet 8,231 feet 1,465 feet 1,455 feet

Add and simplify: 5x+7 / x-6 + 4x / 6 - x Enter the numerator and denominator separately in the boxes below. If the denominator is 1, enter the number

A card is pulled from a deck of card and noted. The card is then replaced, the deck is shuffled, and a second card is removed and noted. What is the probability that both cards are Aces? * 1/13 1/52 2/13 1/169 1/26

Paul opens a savings account with $350. He saves $150 per month. Write a function that illustrates this situation. Function: p(x)= Slope/Meaning in context: m = y-intercept/Meaning in context: b= How much has he saved after 8 months? p= How long will it take Paul to save $2000 in the bank?

Suppose that y varies inversely with x, and y= 10 when x=2. (a) Write an inverse variation equation that relates x and y Equation: (b) Find y when x = 5. y =

In one day, a yoga instructor teaches 3 classes in the morning and 4 classes in the afternoon. The length of each class is m minutes. Which expression represents the total number of minutes the yoga instructor teaches in one day? A. 7m B. 7+ m C. 10m D. 10 + m

A motorboat travels 111 kilometers in 3 hours going upstream. It travels 171 kilometers going downstream in the same amount of time. What is the rate of the boat in still water and what is the rate of the current? Note that the ALEKS graphing calculator can be used to make computations easier. Rate of the boat in still water: Rate of the current:

Among the students in a local school division, ACT scores were normally distributed this year with a mean score of 20.7 and a standard deviation of 5.9. SAT scores were normally distributed with a mean score of 1075 and a standard deviation of 168. Who scored better on their standardized test with respect to the other test takers in the school division, Jamal who took the ACT and score 29 or Shamar who took the SAT and scored 1240? Jamal Shamar Both Jamal and Shamar Neither Jamal or Shamar

Hannah can paint a room in 12 hours. Destiny can paint the same room in 20 hours. How long does it for both Hannah and Destiny to paint the room it they are working together.

A researcher is hired by an alcohol manufacturer to study the connection between alcohol consumption and poor decision making. They approach college students at a bar, explain the study to them, and offer to pay them to participate. Half of the students are given 3 free drinks, while the other half are given free food and non-alcoholic beverages. The researcher then asks them to complete a short study of their decision making ability. Many of the students given alcohol don't complete the study, or write in joke answers, so they throw those results out. Afterwards, they find that there is no difference between the decision making capability of the students who drank and those who did not. Select all of the ethical/procedural mistakes which the researcher made, based on the information given above. You will lose credit if you select incorrect answers. The researcher had a conflict of interest. The researcher used a convenience sample. The researcher risked the health or safety of participants. The researcher did not conduct a blind study. The researcher cherry-picked data. The researcher did not use a control group. The researcher confused correlation with causation. The researcher failed to obtain informed consent.

Solve the rational equation: - 9m / m²-9 + 1 / m+3 = 1 / m-3

Two routes connect an origin-destination (OD) pair with performance functions t₁ = 5 + 4x1 and t2= 7+ 2x2 (with t's in minutes and x's in thousands of vehicles per hour). The total demand for the OD pair is 4000 vehicles. (a) Find the User Equilibrium (UE) flow. (b) Find the System Optimum (SO) flow.

Kevin is an auto mechanic. He spends 3 hours when he replaces the shocks on a car and 2 hours when he replaces the brakes. He works no more than 42 hours a week. He routinely completes at least 2 shocks replacements and 6 brake replacements a week. If he charges $500 for labor replacing shocks and $200 in labor for replacing brakes, how many jobs of each type should he complete a week to maximize his income?

Find the present value of a continuous income stream F(t) = 20 + 6t, where t is in years and F is in thousands of dollars per year, for 30 years, if money can earn 1.9% annual interest, compounded continuously.

There is a spinner with 15 equal areas, numbered 1 through 15. If the spinner is spun one time, what is the probability that the result is a multiple of 3 or a multiple of 5?

How much heat is required to boil 45.0 g of water at it's boiling point? a. 50.2 J b. 102 J c. 18800 J d. 102000 J

A certain forest covers an area of 3500 km. Suppose that each year this area decreases by 6%. What will the area be after 5 years?

The dollar value v (t) of a certain car model that is t years old is given by the following exponential function. v (t) = 26,000(0.92)^t Find the initial value of the car and the value after 12 years.

The drama club is selling tickets to their play to raise money for the show's expenses. Each student ticket sells for $7 and each adult ticket sells for $9.50. There was a total of $883.50 in revenue from all ticket sales and the drama club sold 27 more adult tickets than student tickets. Determine the number of student tickets sold and the number of adult tickets sold.

Scott is using a 12-foot ramp to help load furniture into the back of a moving truck. If the back of the truck is 3.5 feet from the ground, what is the horizontal distance from where the ramp reaches the ground to the truck?

In a certain Algebra 2 class of 26 students, 21 of them play basketball and 7 of them play baseball. There are 2 students who play neither sport. What is the probability that a student chosen randomly from the class plays both basketball and baseball?

A company is considering expanding their production capabilities with a new machine that costs $60,000 and has a projected lifespan of 6 years. They estimate the increased production will provide a constant $11,000 per year of additional income. Money can earn 1.4% per year, compounded continuously. Should the company buy the machine?

A car service charges customers a flat fee per ride (which is higher during rush hour traffic) plus charges for each minute and each mile. Suppose that, in a certain metropolitan area during rush hour, the flat fee is 54, the cost per minute is $0.20, and the cost per mile is $1.30. Let x be the number of minutes and y the number of miles. At the end of a ride, the driver said that the passenger owed $10.30 and remarked that the number of minutes was four times the number of miles. Find the number of minutes and the number of miles for this trip.

A fishbowl shaped like a sphere is filled with water. The fishbowl has a diameter of 16 inches. Which measurement is closest to the volume of water in the fishbowl in cubic inches? A 2,144.66 in.³ B 17,157.28 in.³ C 5,461.67 in.³ D 6,433.98 in.³

Carter bought a pair of shoes online for $64. He used a coupon code to get a 10% discount. The website also applied a 5% processing fee to the price after the discount. How much did Carter pay, in the end?

Given the demand function d(p) = 27 – p², and the supply function s(p) = 6p. Calculate the following: a) The equilibrium price: b) The gains from trade is the sum of the consumer and producer surplus. Calculate the gains from trade

A plane can fly 340 miles in the same time as it takes a car to go 120 miles. If the car travels 110 mph slower than the plane, find the speed of the plane.

A used car has a value of $15,250 when it is purchased in 2012. The value of the car decreases at a rate of 7.5% per year. 1. Write an exponential function that models the value y of the car over x years. 2. To the nearest cent, what will be the value of the car after eight years?

An electrician charges a $20 house call fee plus $30 per hour of work. Which equation represents this relationship? A. y=20+30 B. y=20x + 30 C. y = 30x + 20 D. y = 50x

Frederick's salary varies directly with the hours he works. Last week he earned $328.30 and worked 33.5 hours. If he works 35 hours this week, what will be his salary? A $314.23 B $329.80 C $343.00 D $357.14

One inlet pipe can fill an empty pool in 6 hours, and a drain can empty the pool in 10 hours. How lo it take the pipe to fill the pool if the drain is left open?

Add and/or subtract and then simplify completely: 3p/p²-81 + p/p+9

Subtract and simplify: 7x + 5/5x² - 1x + 5/5x² Numerator preview: Denominator preview: Enter the numerator and denominator separately in the boxes below. If the denominator is 1, enter the number 1. Do not leave either box blank. Answer:

Add and/or subtract and then simplify completely: 4p + 3/p² - 6p+8 + 1/P-4 Numerator preview: Denominator preview: Enter the numerator and denominator separately in the boxes below. If the denominator is 1, enter the number 1. Do not leave either box blank. Answer:

Simplify the expression 2x - 3 / x - 3 + 3 - x / x - 3 and give your answer in the form of f(x) / g(x) Your answer for the function f(x) is : Your answer for the function g(x) is :

Simplify the expression x^2- 8x +12 / x^2- 5x + 6 and give your answer in the form of f(x)/g(x) Your answer for the function f(x) is : Your answer for the function g(x) is:

Tuition for one year at a state university is about $14,000. Denim would like to attend this university and will save money each month for the next 4 years. His parents will give him $6,500 for his first year of tuition. Which plan shows the minimum amount of money Denim must save to have enough money to pay for his first year of tuition? Save $625.00 per month for the next 4 years. Save $156.25 per month for the next 4 years. Save $1,875.00 per month for the next 4 years. Save $250.00 per month for the next 4 years.

A basketball team sells tickets that cost $10, $20, or, for VIP seats, $30. The team has sold 3121 tickets overall. It has sold 222 more $20 tickets than $10 tickets. The total sales are $58,770 How many tickets of each kind have been sold? How many $10 tickets were sold? How many $20 tickets were sold?

Evaluate the sine, cosine, and tangent of the angle without using a calculator. (If an answer is undefined, enter UNDEFINED.) -135° sin θ = cos θ = tan θ =

Suppose that y varies directly with x, and y=8 when x = 20. (a) Write a direct variation equation that relates x and y. Equation: (b) Find y when x = 7. y =

A lemonade seller calculates that it costs $20 to produce 100 glasses of lemonade and $35 to produce 400 glasses of lemonade. Assume the relationship between the cost and the number of glasses of lemonade produced is linear. Of the choices given, what is the most reasonable estimate for producing 700 glasses of lemonade? $35 $40 $50 $70