Four people can mow a lawn in 6 hours. How many more people will be needed to mow the lawn in 4 hours, assuming each person mows at the same rate?
6 people
We can use the "see-saw" principle, here
4 people * 6 hours = x people * 4 hours
24 = x * 4 divide both sides by 4
24 / 4 = x = 6 people
Thanks!