The average of 22 numbers is 37.5. The average of first 12 number is 40.6 and that of the last 12 number is 35.4.If 11th and 12th number are excluded ,then what is the average of remaining number?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 36.9
Given :
The average of 22 numbers is 37.5.
The average of first 12 number is 40.6
Average of the last 12 number is 35.4.
Formula used :
Average = Sum of observation/number of observations ---- (1)
Calculations :
Using equation (1), we get
Sum of 22 numbers = 37.5 × 22
⇒ 825
Sum of first 12 numbers = 12 × 40.6
⇒ 487.2
Sum of last 12 numbers = 12 × 35.4
⇒ 424.8
Sum of first and last 12 numbers = 912
Sum of 11th and 12th number = 912 - 825
⇒ 87
If 11th and 12th are excluded, the average of the remaining 20 numbers
⇒ (825 - 87)/20
⇒ 738/20
⇒ 36.9