10 factories, working for h hours per day, can produce P

[BTGmoderatorDC]

10 factories, working for h hours per day, can produce P units of cars in every 5 days. Each factory produces car at the same constant rate. What is the additional time taken by the 10 factories to produce 2P units of cars, if they work for h/2 hours per day instead of h hours per day?


A. 0
B. 2
C. 5
D. 10
E. 20

OA D

Source: e-GMAT

[GMATGuruNY]

10 factories, working for h hours per day, can produce P units of cars in every 5 days. Each factory produces car at the same constant rate. What is the additional time taken by the 10 factories to produce 2P units of cars, if they work for h/2 hours per day instead of h hours per day?


A. 0
B. 2
C. 5
D. 10
E. 20

When the factories work for h hours per day, P cars are produced every 5 days, with the result that 2P cars are produced every 10 days.
If the daily work-hours are CUT IN HALF -- to h/2 hours per day -- the number of days required for 2P cars will DOUBLE to 20.
Since the time for 2P cars increases from 10 days to 20 days, the number of additional days required = 20-10 = 10.

The correct answer is D.

[Scott@TargetTestPrep]

10 factories, working for h hours per day, can produce P units of cars in every 5 days. Each factory produces car at the same constant rate. What is the additional time taken by the 10 factories to produce 2P units of cars, if they work for h/2 hours per day instead of h hours per day?


A. 0
B. 2
C. 5
D. 10
E. 20

OA D

Source: e-GMAT

Normally, the factories will take 10 days to produce 2P units of car if they work h hours per day. However, if they only work h/2 hours per day, the number of days will be doubled to 20 to produce 2P units of car. Therefore, they need an additional 10 days.

Answer: D