Madhya Pradesh Police Exam Model Paper 1

Given:
The average of 12 numbers is 40 and the average of the first 7 numbers is 30.
Concept used:
Sum of all terms = Average × Total number of terms
Calculation:
The average of 12 numbers is 40
∴ Sum of numbers $=12\times 40=480$
And, the average of the first 7 numbers is 30
∴ Sum of numbers $=7\times 30=210$
Now, the sum of the remaining numbers $=480\mathit{–}210=270$
∴ Average of remaining numbers $=270/5=54$