202k views
0 votes
Working alone, it would take Shandra 45 minutes to mow the lawn. To mow the same lawn, also working alone, it would take Kelly 1 hour and 15 minutes. If they work together, the girls believe it will take them 1 hour to mow the lawn.

Which best describes the reasonableness of their solution?

User Scrrr
by
8.3k points

2 Answers

5 votes
You could add the time it takes them individually together and divide by 2. That would give you the average, which is 1 hour.
User ThemesCreator
by
7.9k points
2 votes

Answer:

While working together, they will complete the work in 28.125 minutes

Explanation:

Working alone, it would take Shandra 45 minutes to mow the lawn.

Working alone, it would take Kelly 1 hour and 15 minutes. to mow the lawn. In minutes this becomes
60+15=75 minutes.

So, when they are working together, they will complete 1 job.

Lets the time taken by both working together be t

Equation forms:


(t)/(45) +(t)/(75) =1

=>
(5t+3t)/(225) =1

=>
(8t)/(225) =1

=>
8t=225

t = 28.125 minutes

Hence, while working together, they will complete the work in 28.125 minutes which is very less than their estimation.

User Tamas
by
8.5k points