Question 703170
D=RT
LET X & (X+20) BE THE SPEEDS.
800=(X+X+20)*5
800=(2X+20)*5
800=10X+100
10X=800-100
10X=700
X=700/100
X=70 MPH. FOR THE SLOWER TRAIN.
70+20=90 MPH. FOR THE FASTER TRAIN.
PROOF:
800=(70+90)5
800=160*5
800=800