A student needed to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found the mean to be 12. What is the value of x?
Choose the correct choice from the following answers.
A) 7	B) 8	C) 9	D) 6	E) 5
(3+11+7+9+15+13+8+19+17+21+14+x)/12 =12   ⇒(137+x)/12=12   ⇒137+x=144   ⇒x=144−137=7   7nswer is 7.
<result>A</result>
A student needed to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found the mean to be 12. What is the value of x?