GAUSS8 2018 Problem 19

The mean (average) height of a group of children would be increased by 6 \mathrm{~cm} if 12 of the children in the group were each 8 \mathrm{~cm} taller. How many children are in the group?

Answer Choices
A. 16
B. 14
C. 21
D. 26
E. 9