Answer
2.25 hr
Work Step by Step
Use a unit fraction with hour (the unit for your answer) in the numerator, and min (the unit being changed) in the denominator. Because 1 hour = 60 min, the necessary unit fraction is
(1 hr)/(60 min)
Multiply 135 min times the unit fraction
135 min * (1 hr)/(60 min) = 9/(4 ) hr = 2.25 hr