###
**The average of 20 numbers is 12. The average of the first 12 numbers is 11 and that of the next 7 numbers is 10. The last number is ?**

A. 40
B. 38
C. 48
D. 50
**Answer: Option B**

## Show Answer

Solution(By Apex Team)

$\begin{array}{l}\text{Let the last number = x}\\
\text{According to the question,}\\
\text{⇒ 12 × 11 + 7 × 10 + x = 20 × 12}\\
\text{⇒ 132 + 70 + x = 240}\\
\text{⇒ x = 240 – 202}\\
\text{⇒ x = 38}\end{array}$

## Related Questions On Average

### Ajit has a certain average for 9 innings. In the tenth innings, he scores 100 runs thereby increasing his average19 people went to a hotel for combine dinner party 13 by 8 runs. His new average is:

A. 20B. 21

C. 28

D. 32

### Find the average of all the numbers between 6 and 34 which are divisible by 5.

A. 18B. 20

C. 24

D. 30

### In a family, the average age of a father and a mother is 35 years. The average age of the father, mother and their only son is 27 years. What is the age of the son?

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### If the arithmetic mean of 0, 5, 4, 3 is a, that of -1, 0, 1, 5, 4, 3 is b and that of 5, 4, 3 is c, then the relation between a, b, and c is.

A. a = b = cB. a : b : c = 3 : 2 : 4

C. 4a = 5b = c

D. a + b + c = 12