Question

Ana and Bella are sisters.They are responsible for keeping the

family's driveway clear of snow.If they work together they can
complete the shoveling in 30 minutes.
One day Ana had to do the job alone.It took her 40 minutes.How long
would it have taken Bella to shovel the same amont alone?You can
assume that each girl always shovels at a constant speed.

Answer 1

Bella can complete work alone in 120 minutes

Explanation:

Ana and Bella together can complete the shoveling in 30 minutes.

They can do a part of work in 1 minute =
`(1)/(30)`

Ana can do work alone in 40 minutes

She can do part of work in 1 minute =
`(1)/(40)`

So, Bella can do a part of work in 1 minute =
`(1)/(30)-(1)/(40)`

=
`(1)/(120)`

Bella can do
`(1)/(120)` part of work in 1 minute

Bella can do whole work in minutes = 120

Hence Bella can complete work alone in 120 minutes