. Spencer and his good buddy Preston are both mechanics at a shop that does oil changes. They are in a friendly competition to see who can complete the most oil changes in one day. Spencer has already finished 8 oil changes today and can complete more at a rate of 3 oil change per hour. Preston just came on shift and can finish 5 oil changes every hour. 6. Write an equation that can be used to find the number of hours (h) it will take for the two buddies to complete the same number of oil changes.