students of 3 different classes appeared in common examination. pass average of 10 students of first class was 45 %, pass average of 15 students of second class was 60 % and pass average of 25 students of third class was 80 % then what will be the pass average of all students of 3 classes?	Pick:
A) 74 %	B) 75 %	C) 67 %	D) 72 %	E) none
<gadget id="calculator">10 * 45</gadget>
<output>450</output>

<gadget id="calculator">450 / 100</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">15 * 60</gadget>
<output>900</output>

<gadget id="calculator">900 / 100</gadget>
<output>9</output>

<gadget id="calculator">(9/2) + 9</gadget>
<output>27/2 = around 13.5</output>

<gadget id="calculator">25 * 80</gadget>
<output>2_000</output>

<gadget id="calculator">2_000 / 100</gadget>
<output>20</output>

<gadget id="calculator">(27/2) + 20</gadget>
<output>67/2 = around 33.5</output>

<gadget id="calculator">(67/2) * 100</gadget>
<output>3_350</output>

<gadget id="calculator">10 + 15</gadget>
<output>25</output>

<gadget id="calculator">25 + 25</gadget>
<output>50</output>

<gadget id="calculator">3_350 / 50</gadget>
<output>67</output>

<result>C</result>
students of 3 different classes appeared in common examination. pass average of 10 students of first class was 45 %, pass average of 15 students of second class was 60 % and pass average of 25 students of third class was 80 % then what will be the pass average of all students of 3 classes?
divide(multiply(add(add(divide(multiply(10, 45), const_100), divide(multiply(15, 60), const_100)), divide(multiply(25, 80), const_100)), const_100), add(add(10, 15), 25))
solution : sum of pass students of first , second and third class , = ( 45 % of 10 ) + ( 60 % of 15 ) + ( 80 % of 25 ) = 4.5 + 9 + 20 = 33.5 total students appeared , = 10 + 15 + 25 = 50 pass average , = 33.5 * 100 / 50 = 67 % . answer : option c