3. The mean of five numbers is 6. What is the sum of the numbers?
A. 11
B. 12
C. 15
D. 30
4. In a class of 15 students, seven have an average of 86 while the rest have an average of 82. What is the average of the whole class?
A. 82
B. 82.8
C. 83.9
D. 84
5. Which measure of central tendency should a businessman use when buying items for his store?
A. mean
D. range
B. median
C.mode
D. range​