sandy wrote:
If a baker made 60 pies in the first 5 hours of his workday, by how many pies per hour did he increase his rate in the last 3 hours of the workday in order to complete 150 pies in the entire 8- hour period?
(A) 12
(B) 14
(C) 16
(D) 18
(E) 20
We know
Work = Rate * Time
So for the first 5 hours we have;
60 = Rate * 5
Rate = 12 pies/hr
For the next 3 hour we have;
(150-60) = Rate * 3 (Since total pies is 150 and 60 pies were already prepared within 5 hrs; so in 3 hrs he prepare 150-60 pies)
Rate = 30 pies
Therefore the rate increased = 30 -12 = 18 pies/hr