Answer:
time to frame room together = 4/3 hrs
Explanation:
Jerry can frame a room in 2 hours while Jake can frame the same room for 4 hours. We need to find the rate at which each of them can frame the room.
Jerry frame a room for 2 hrs
Framing done by Jerry in 1 hr will be 1/2 room frame
Jake frame same room for 4 hrs
Framing done by Jake in 1 hr will be 1/4 room frame
Therefore, the rate working together will be
1/2 + 1/4 = (2 + 1)/4 = 3/4
Both of them frame 3/4 th of the room in 1 hr
To frame 1 room together they will spend what time
cross multiply
time to frame room together = 1 ÷ 3/4
time to frame room together = 1 × 4/3
time to frame room together = 4/3 hrs