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 :
Answer & explanation
Correct answer: option 2
Last number = (Sum of 20 numbers) - (Sum of first 12 + Sum of next 7)
= (240) - [(12 × 11) + (7 × 10) ]
= (240) - (132 + 70) = 38