In assembling a Bluetooth device, a factory uses one of two kinds of modules. One module costs $8 and the other one, that is cheaper, costs $3. The factory holds a $100 worth stock of 25 modules. How many of the modules in the stock are of the cheaper kind?	Select the correct option.
A) 21
B) 20
C) 22
D) 23
E) 24
So the number of $3 modules must be 20 so that the leftover 5 modules are of $8 which will give a total value $100. 20*3+5*8 = 60+40= 
<gadget id="calculator">60+40</gadget>
<output>100</output>
100.   Answer : 20
<result>B</result>
In assembling a Bluetooth device, a factory uses one of two kinds of modules. One module costs $8 and the other one, that is cheaper, costs $3. The factory holds a $100 worth stock of 25 modules. How many of the modules in the stock are of the cheaper kind?