Solution
Powerful-Riding Motor
Manny used the PRM for 90% of the time. This means we have to find 90% of 70 minutes, because it takes 70 minutes to cut the entire lawn using the PRM.
90% x 70= 63
So it took 63 minutes to cut 90% of the lawn.
Push Mower
Manny used the push mower to mow 10% of the lawn. It takes 5 hours or 300 minutes to mow the whole lawn using the push mower. So we need to find 10% of 300.
10% x 300= 30
It took 30 minutes to mow the last 10% of the lawn.
Total
63(90%)+30(10%)=93
It took Manny 93 minutes or 1 hour and 33 minutes to mow the entire lawn.