Question

John can finish a paper route in 4 hours, and Andrew

can finish the same paper route in 7 hours. If they work together,
how long would it take them to finish the paper route?

Answer 1

in one hour, John does 1/5 of the route and Andrew does 1/7

Together, they do 1/x of the whole route, x being unknown.

(1/5)+(1/7)=(1/x) Multiply everything by 35x, the common denominator

7x+5x+35

12x=35

x=35/12 or 2 11/12 hours, or 2h55m

Explanation: