Question

Show an equation and a solution for the problem. Crane A can unload a ship in 10 hours and crane B can unload it in 14 hours. How long will it take the two cranes to unload the ship working together? Round to the nearest tenth.

Answer 1

In problems of these types, find what fraction of a job each one will do in 1 hour separately first.
Crane A can unload 1/10th of the ship in 1 hour
Crane B can unload 1/14th of the ship in 1 hour
Assume working together A & B can unload the ship in x hours
Then working together A & B can unload 1/x th of the ship in 1 hour.
Therefore, 1/10 + 1/14 = 1/x
solve for x.