Question 334727
D=rt
D =rt1
D= 40t1
similarly 
D=45t2
40t1=45t2
t1/t2 =45/40=9/8
t1=9t2/8
t1+t2= 4
9t2/8 +t2 =4
17t2 = 32
t2 =32/17hours and t1=36/17hours.
D =45*32/17 =40*36/17
D= 84.71 miles.