pritam.ryders wrote:IF 6 machines can do complete a piece of work in 12 days then how many extra machines is required to complete the same work in 8 days?
The number of machines here is the RATE -- how much work is completed per day.
Thus, the amount of work = r*t = (number of machines)(number of days).
Since the value of the work is not changing, we get the following INVERSE proportion:
(number of machines)(number of days) = (number of machines)(number of days)
In the equation above, as the number of machines INCREASES, the number of days DECREASES, so that the SAME AMOUNT OF WORK is completed in each case.
Since 6 machines can complete the job in 12 days, and we need to determine the number of machines required to complete the job in 8 days, we get:
(6)(12) = (x)(8)
x = 9.
Since 9 machines are needed, the number of machines that must be added to the 6 existing machines = 3.
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