<h2><u>
Answer:</u></h2>
The correct answer is:
Their estimate is longer than the time it will actually take.
( Since, Estimated time-- 1 hour=60 minutes
Time actually taken= 28.125 minutes )
<h2><u>
Step-by-step explanation:</u></h2>
Time taken by Shandra alone to mow the field is: 45 minutes.
Time taken by Kelly alone to mow the field is: 1 hour 15 minutes.
We know that:
1 hour=60 minutes
Hence, 1 hour 15 minutes=60 minutes +15 minutes=75 minutes.
By looking at the time we consider that the total work be of 225 units.
This means that the Efficiency of Shandra is: 225/45=5 units/minutes.
Similarly,
Efficiency of Kelly is: 225/75=3 units/minutes.
- Now, when they will work together there efficiency will be added.
Hence, 5+3=8
Hence, the time taken by both of them when they work together is:
225/8
= 28.125 minutes.
But it was estimated that they took 1 hour=60 minutes.
Hence, there estimation of time taken was longer than what they actually took.