Question

The mean of 5 observations is 12. If the mean of the first 3 is 10, then find the mean of the other two.

• A. 10
• B. 15
• C. 5
• D. 9

Answer 1

The correct option is B

15

Mean of 5 numbers =12

Mean=total sum of observation/total number of observations

So the total sum would be=mean×total number of observation. 12×5=60

Mean of first 3 is 10

So the sum total of first 3 would be 10×3=30

=>Total sum of rest 2 numbers is 60-30=30

=>Their mean is $\frac{30}{2}$=15