Jane works 3 times as fast as Eleanor. If they work together they can do a job in 21 minutes. How long does it take Eleanor to do the job by herself?

The work rate when they work together is much higher than when Eleanor

does the job herself.

Reasons:

Jane's work rate = 3 × Eleanor's work rate

The time it takes both Jane and Eleanor to do a job = 21 minutes

Required:

The time it would take Eleanor to do the job herself.

Solution:

Let x represent the portion of the job performed by Eleanor in the 21

minutes, we have;

The portion performed by Jane = 3 × x

Therefore;

The job done when they work together for 21 minutes = x + 3·x = 4·x

The time it takes Eleanor to do the job portion, x = 21 minutes

Therefore;

The time it will take Eleanor to do a job of 4·x = 4 × 21 minutes = 84 minutes

Learn more about work word problems here:

link

link

1 hour and 24 min

Step-by-step explanation:

Jane does 3/4 job done in 21 min

Eleanor does 1/4 job done in 21 min

21*4=84

60+24

1 hour and 24 min

step-by-step explanation:

it's is b

step-by-step explanation: