Question 521595
V1=V2+15
t1=350/V1=350/(V2+15)
t2=350/V2

t1+3=t2
350/(V2+15)+3=350/V2

multiplying everything by (V2+15)V2

350V2+3V2^2+45V2=350V2+5250
3V2^2+45V2^2-5250=0

Solution is : V2=35mph

V1=35+15=50mph