There are A girls in a class, and their average height is M inches. In the same class, there are B boys with an average height of N inches. What is the average height of all the students in the class?	Choose the correct choice from the following answers.
A) (X + Y)/(M + N)  B) (M + N)/(X + Y)  C) (AM + BN)/(A + B)  D) (XM + YN)/(X + Y)  E) MN/XY
Total height = AM+BN   No of students = A+B   Avg = (AM+BN)/(A+B)   Answer is (AM + BN)/(A + B)
<result>C</result>
There are A girls in a class, and their average height is M inches. In the same class, there are B boys with an average height of N inches. What is the average height of all the students in the class?