Given: Shandra can do the complete work in 45 minutes.
So, Shandra's 1-minute work = 1 / 45 and
Kelly can do the same complete work in 1 hour and 15 minutes = 75 minutes.
So, Kelly's 1-minute work = 1 / 75
Now, we shall calculate Shandra's and Kelly's 1-minute work
By both 1 minute work = (1/45) + (1 / 75) = 8 / 225
∵ 8 /225 Parts can be completed by both = in 1 minute
∴ Complete work (1) can be completed by both = 225 / 8 minutes
or, = in 28 minutes and 7.5 second
Hence, the assumption taken by both was incorrect.
The best described time will be 28 minutes and 8 seconds.
