Question 40454
rate1 + rate2 = combined rate
(1 ft / 135 min) + (1 ft / 45 min) = 1 ft / x min)
LCD is 135
1/135 + 3/135 = 1/x
4/135 = 1/x
4x = 135
x = 33.75
33 min 45 sec with both pipes open