A person can plow out all the driveways on his street with his new four-wheel-drive truck in 6 hours. using a snow blade on a lawn tractor, his neighbor can plow out the same number of driveways in 10 hours. how long would it take them to do the work together?

Answer 1

it will take x hours, where
1/x = 1/6 + 1/10
now just find x

Answer 2

A rectangular sandbox is surrounded on all sides by a strip of grass that is 5 feet wide on all sides. The length of the sandbox is 4 feet more than the width, and the
total area for the sandbox and the grass is 189 square feet. Find the dimensions of the sandbox.

Answer 3

If the width is w, then the length is w+4
Now, they have told you that
(w+10)(w+4+10) = 189
so finish it off.

check for typos, since the dimensions are apparently not integers.