Question

Nancy can do a typing job in 8 hours, when Carole helps her, they can do the job in 5 hours. How many hours would it take Carole to do it alone

Answer 1

Answer:
`(40)/(3)\ \text{hours}`

Explanation:

Nancy can do typing job in 8 hours

i.e. in 1-hour nancy can
`(1)/(8)` part of work

Together they can do that work in 5 hours

or in 1 hour
`(1)/(5)` part of work is done

suppose Carole takes x hours for the work

so, in 1 hour
`(1)/(x)` part is done

If both work together for 1 hour then we can write

`(1)/(8)+(1)/(x)=(1)/(5)`

`(1)/(x)=(1)/(5)-(1)/(8)`

`x=(40)/(3)\ \text{hours}`