The average of twenty five numbers is 18, the average of first twelve numbers is 14 and that of last twelve numbers is 17. The thirteenth number is ____.
A72
B78
C85
D28
The average of twenty five numbers is 18, the average of first twelve numbers is 14 and that of last twelve numbers is 17. The thirteenth number is ____.
A72
B78
C85
D28