GreenlightTestPrepI thought about this problem from another point, and I always get 8.
Where I am wrong, if I am?
Step 1: Find Speeds
Donovan speed in minutes:
400/45 -> (400*3)/4
Michael speed in minutes:
400/40 -> (400*2)/3
Step 2: Find the speed difference
(400*3)/4 - (400*2)/3 = 100/3
Step 3: Find how many minutes it will take to finish 400 meters circle with 100/3 speed
400 / (100/3) = 12 minutes
Step 4: How many meters Michael drive in 12 minutes
( (400*2)/3 ) * 12 = 3,200
Step 5: Find how many 400-meter circles we have in 3,200 meters
3,200 / 400 = 8
Final Result:
Michael drove 8 circles.
Donovan has one extra circle so he had 9, but the question asks about Michael.
Am I wrong about my approach?