Answer:
70 minutes
Step-by-step explanation:
We assume that the time is proportional to the area and inversely proportional to the number of members.
Then the time for the second job will be the first job's time multiplied by ...
20/9 . . . the inverse of the ratio of members painting
4200/4800 = 7/8 . . . the ratio of area being painted
The time it would take is ...
(36 min)(20/9)(7/8) = 70 min
It will take the smaller team 70 minutes to paint a 4200 ft² wall.
