Work Problem

Question

Trent can deliver his newspapers in 60 minutes. It takes Lois 30 minutes to do the same route. How long would it take them to deliver the newspapers if they work together? 

Answer 1

t/60 + t/30 = 1

t + 2t = 1

3t = 1

t = 1/3

 

They get done in 20 minutes

Answer 2

Trent can run 1/2 of a route in 30 minutes. Lois can run 1 route in 30 minutes. So working together, they can run 3/2 of a route in 30 minutes.

Multiplying by 2 gives 3 routes in 60 minutes.

Dividing by 3 gives 1 route in 20 minutes.

 

So it takes them 20 minutes to run the route together.