ajit257 wrote:

Working simultaneously and independently at an identical constant rate, 4 machines of a

certain type can produce a total of x units of product P in 6 days. How many of these

machines, working simultaneously and independently at this constant rate, can produce a

total of 3x units of product P in 4 days?

A. 24

B. 18

C. 16

D. 12

E. 8

4 machines----------x units-----------6days

4 machines---------3x units-----------3*6 = 18 days

M machines---------3x unites----------4 days

The number of days and the number of machines which produce a certain number of units (in this case 3x) are inversely proportional.

This is because all the machines have the same constant rate.

Necessarily 4*18=M*4, therefore M = 18.

Answer B

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