Final answer:
The front wheel will do 12 more cycles than the back wheel after every 42 meters.
Step-by-step explanation:
To find the distance at which the front wheel does 12 more cycles than the back wheel, we first need to determine the number of cycles each wheel completes per meter. The circumference of the front wheel is 2.5m, so it completes 1 cycle every 2.5m. The circumference of the back wheel is 4m, so it completes 1 cycle every 4m. Therefore, the front wheel completes 12 more cycles than the back wheel after every 12(4m - 2.5m) = 42m.
Therefore, the front wheel will do 12 more cycles than the back wheel after every 42 meters.