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