Question 870860
D=RT
D=4(T+7.5) FOR THE SLOWER RUNNER
D=5T FOR THE FASTER RUNNER
4(T+7.5)=5T
4T+30=5T
4T-5T=-30
-T=-30
T=30 SEC IS THE RUN TIME.
PROOF:
4(30+7.5)=5*30
4*37.5=150
150=150