Problem Solving

A runs 25% faster than B and is able to give him a start of 7 meters to end a race in dead heat. What is the length of the race?

A.10 meters
B. 25 meters
C. 45 meters
D. 15 meters
E. 35 meters

Can anyone please help solve the above problem?

Thanks!

OA [spoiler][E][/spoiler]

Let's assume that the length of the race track is x meters and that Runner A's speed 1.25y and runner B's speed is y. Since the problem tells us that Runner A will finish the race with runner B in dead heat if he/she gives runner B a head start of 7 meters, we can already take into consideration that Runner A will finish at the same time as runner B when they finish the race. So:

x-7 is the distance that runner B will run since he/she gets a head start of 7 meters.

x is the distance that runner A will run.

x-7/y=x/1.25y
x-7/y=4x/5y
Multiply both sides by y and you get x-7=4x/5
x=35 E.