Question

Albert and his good buddy Brad 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. Albert has

already finished 6 oil changes today, and can complete more at a rate of 1 oil change per

hour. Brad just came on shift, and can finish 3 oil changes every hour. Sometime during the

day, the friends will be tied, with the same number of oil changes completed. How long will

that take?

Answer 1

3 hours

Explanation:

Albert already finished 6 oil changes

He works at a rate of 1 oil change per hour

Let x be the number of hour at which they will be tied ie equal

For Albert, we have the sum of a constant and his hourly work rate: 6+1x

Brad works at a rate 3 oil changes every hour: 3x

6+1x=3x

3x-1x=6

2x=6

x=6/2=3

After 3 hours, they will be tied.