If the average of 5, 9 ,M and n is 12 m what is the average of (m +7) and (n -3) ?
A
21
B
19
C
17
D
14
Correct Answer: 19
here,5+9+m+n4=12=> m + n = 34 …………(i)and,Av of (m+7) and (n-3) = (m+7)+(n-3)2=m+n+42=34+42 ………………….. [m+n=34]= 19