Six computers, each working at the same constant rate, together can process a certain amount of data in 15 days. How many additional computers, each working at the same constant rate, will be needed to process the same amount of data in 5 days?	Choose the correct choice from the following options.
A) 3
B) 5
C) 6
D) 9
E) 12
Explanation: If six computers require 15 days to process the data, thats   a total of 90 computer-days the product of 6 and 15. If you change the number   of computers or the number of days, 90 will have to remain the product, whether   that means 90 days of one computer or one day with 90 computers.   In 5 days, the number of computers is:   5c = 90   c = 18   18 computers is 12 more than the 6 that it took to do the job in 15 days, so   the correct choice is (12).
<result>E</result>
Six computers, each working at the same constant rate, together can process a certain amount of data in 15 days. How many additional computers, each working at the same constant rate, will be needed to process the same amount of data in 5 days?