You are told that 3 secretaries can do 12 pages in 5 minutes.

One secretary can do 1/3 as much = 4 pages in 5 minutes.

The pages per minute fromeach secretaryis:

The pages per minute for 6 secretaries will be 6 times as high: 0.8*6 = 4.8

So finally, if you have 6 secretaries doing a total of 4.8 pages per minute, how long will it take to do 32 pages?

Spoiler: