Two car washers, Lydia and Jackie, are working on your car. Lydia can complete the work in 2 hours, while Jackie can complete the work in 1 hour. How many hours do the car washers take if they work together?

Question

ashlyn_loves_cats · Answer

an hour and 30 mins

jackman · Answer

these are the options
1/2
3/2
2/3
4/3

mathstudent55 · Answer

If Jackie can complete the job alone in 1 hour, then when both work together, they must take less than 1 hour.

mathstudent55 · Answer

Jackie completes the job in 1 hour.
In 1 hour, Jackie does 1/1 = 1 full job

Lydia completes the job in 2 hours.
In 1 hour, Lydia completes 1/2 of the job.

Working together, they take x time to complete the job.
In 1 hour, they do 1/x of the job.

$\dfrac{1}{1}  + \dfrac{1}{2} = \dfrac{1}{x} $

Solve for x.