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 =12×40=480 And, the average of the first 7 numbers is 30 ∴ Sum of numbers =7×30=210 Now, the sum of the remaining numbers =480–210=270 ∴ Average of remaining numbers =270/5=54