The average of 22 numbers is 52 The average of the first 8 numbers is 48 and the average of nex...........

Quantitative Aptitude (CPO) Average

The average of 22 numbers is 52. The average of the first 8 numbers is 48 and the average of next 11 numbers is 54. The 20^th

number is 7 less than the 21^stnumber and 21^st number is 4 more than 22^ndnumber. What is the average of the 20^thand 22^nd

numbers?

This questions was previously asked in

SSC CPO 13th-March-2019-Shift-1

52.5

53.5

- The total sum of the 22 numbers is \( 22 \times 52 = 1144 \).

- The sum of the first 8 numbers is \( 8 \times 48 = 384 \).

- The sum of the next 11 numbers is \( 11 \times 54 = 594 \).

- The sum of the last three numbers (20th, 21st, and 22nd) is \( 1144 - 384 - 594 = 166 \).

- Let the 22nd number be \( x \). Then, the 21st number is \( x + 4 \). The 20th number is \( (x + 4) - 7 = x - 3 \).

- Equation: \( (x - 3) + (x + 4) + x = 166 \).

- Simplify to \( 3x + 1 = 166 \).

- Solve for \( x \): \( 3x = 165 \Rightarrow x = 55 \).

- So, the 20th number is 52, and the 22nd is 55.

- Average of 20th and 22nd numbers: \( \frac{52 + 55}{2} = 53.5 \).

Correct Answer: Option: 4 - 53.5

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