Question

Find the mean of the 32 numbers, such that if the mean of 10 of them is 15 and the mean of 20 of them is 11. The last two numbers are 10.

Answer 1

Explanation:

Mean of 11 number=35

Mean of 11 number=35Sum of 11 number=35×11=385

Mean of 11 number=35Sum of 11 number=35×11=385Mean of first 6 number=32

Mean of 11 number=35Sum of 11 number=35×11=385Mean of first 6 number=32Sum of 6 number=32×6=192

Mean of 11 number=35Sum of 11 number=35×11=385Mean of first 6 number=32Sum of 6 number=32×6=192Mean of last 6 number=37

Mean of 11 number=35Sum of 11 number=35×11=385Mean of first 6 number=32Sum of 6 number=32×6=192Mean of last 6 number=37Sum of 6 number=37×6=222

Mean of 11 number=35Sum of 11 number=35×11=385Mean of first 6 number=32Sum of 6 number=32×6=192Mean of last 6 number=37Sum of 6 number=37×6=222∴ Sixth number=(192+222)−385

Mean of 11 number=35Sum of 11 number=35×11=385Mean of first 6 number=32Sum of 6 number=32×6=192Mean of last 6 number=37Sum of 6 number=37×6=222∴ Sixth number=(192+222)−385⇒414−385=29