Question

Five people can mow a lawn in 12 hours. How many more people are needed to mow the lawn in just 3 hours, assuming each person mows at the same rate?

Answer 1

If five people can do it in 12 hours, then you divide and see how long it takes each person. then you figure the rate for how many hours per person. then you figure out how many peopl it takes to do it all in 3 hours

Answer 2

The number of people mowing and the time required to mow are inversely proportional. Letting n be the number of people and t be the amount of time, we have nt = (5)(12)= 60 because 5 people can mow a lawn in 12 hours. If m people can mow the lawn in 3 hours, then we must have m(3) = 60, so m=20. Therefore, we need to add 20-5 = 15 people to the job.