A student was asked to find the arithmetic mean of the number 3,11,7,9,15,13,8,19,17,21,14 and x. He found the mean to be 12. what should be the number in place of x ?  Answers:
A) 3
B) 7
C) 17
D) 31
E) 32
Solution   Clearly, we have(3+11+7+9+15+13+8+19+17+21+14+X/12) = 12   or 137+x = 144 or x = 144-137= 
<gadget id="calculator">144-137</gadget>
<output>7</output>
7. Answer 7
<result>B</result>
A student was asked to find the arithmetic mean of the number 3,11,7,9,15,13,8,19,17,21,14 and x. He found the mean to be 12. what should be the number in place of x ?