Answer
John's Time = 2.25 hours
Mary's Time = 2 hours
Work Step by Step
x = John's Time
y = Mary's Time
c = John's Distance
d = Mary's Distance
x = c/60
y = d/40
c = d + 35
d = 40(x + .25)
Expand d and plug into c:
c = 40x + 45
Now plug c into x and multiply both sides by 60:
60x = 40x + 45
Divide all terms by 60 and simplify:
x = 2/3x + 3/4
Subtract 2/3x from both sides:
1/3x = 3/4
Divide both sides by 1/3:
x = 9/4
x = 2.25
John travelled for 2.25 hours. Mary travelled for 15 minutes less, so she drove for 2 hours.
