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?

Their estimate is wrong, as they are taking almost half the estimated time to complete the work.

Step-by-step explanation:

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. In minutes it becomes 75 minutes.

If they work together, the girls believe it will take them 1 hour to mow the lawn.

Let 't' is the time taken to complete the work working together.

t = 28.125 minutes

We can see that the it will take 28.125 minutes if they are working together, but they believed that it will take them 1 hour to do so.

So, their estimate is wrong, as they are taking almost half the estimated time to complete the work.

a = 11 : 4

b = 38

c = 1 for every 6