anujtsingh wrote:

In assembling a Bluetooth device, a factory uses one of two kinds of modules. One module costs $6.25 and the other one, that is cheaper, costs $2.50. The factory holds a $70 worth stock of 22 modules. How many of the modules in the stock are of the cheaper kind?

(A)4

(B)8

(C)12

(D)16

(E)18

It is easy go : consider x is count of costlier module. y is count of cheaper module.

6.25*x + 2.5*y = 70;

x+y = 22;

by solving these two equation we get y = 18

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Thanks,

AB

+1 Kudos if you like and understand.