All members of our painting team paint at the same rate. If 20 members can paint a 4800 square foot wall in 36 minutes, then how long would it take for 9 members to paint a 4200 square-foot wall, in minutes?

  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.

8

step-by-step explanation: