The age of a rock sample at one location is 8.64 million

Last updated: 7/26/2022

The age of a rock sample at one location is 8.64 million years old and the age of a rock sample at the other location is 6.25 million years old. One location is 87.4km farther from the mid-ocean ridge than the other. What is the speed at which the plate is moving between the two locations?