Question 616489
t/d+t/b=1
d=t+20
b=t+5
t/(t+20)+t/(t+5)=1
t=-10 t=10
t can't be negative.
t=10
d=30
b=15
30/15=d/b=2/1 or 2 to 1 ie 2:1 or twice as fast