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By​ himself, a person can mow his lawn in 24 minutes. If his daughter​ helps, they can mow the lawn together in 20 minutes. How long would it take his daughter to mow the lawn by​ herself?

User VRC
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1 Answer

3 votes

Answer:

It would take 120 minutes to mow the lawn by herself.

Explanation:

The person's rate is
(1 lawn)/(24 minutes) =(1)/(24)(lawn)/(minute).

The dauther's rate is
(1 lawn)/(t).

The combined rate is
(1lawn)/(20minutes).

So, as this the same lawn if we use the formula for combined rates we can get the answer

Person's Rate × Combined time + Daugther's Rate × Combined time =1


(1)/(24)20minutes+(1)/(t) 20minutes=1

We have to multiply all the equation by 24t:

20t+480=24t

t=120 minutes

User Beyondtheteal
by
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