each gardener takes 3*90 = 270 minutes to do the job alone.
So, since 15 = 270/18
It will take a total of 18 gardeners.
It takes for three gardeners 90 minutes to weed a garden. If the job is to be done in only 15 minutes, how many more gardeners need to be put on the jobs?
4 answers
Good ....
Good
Good ...felling better by observing this answer