Question

There are 15 boys and 10 girls in a hall, each holding coins in their hand.The mean number of coins for the children is 10 The mean number of coins for the boys is 8Work out the mean number of coins for the girls.

Answer 1

13 coins

Explanation:

There are 25 kids in total.

The fraction of kids that are boys and girls are:

`B=(15)/(25)=0.6\\B=(10)/(25)=0.4`

The mean number of coins for all kids is given by:

`M=B*M_B+G*M_G`

If we are given that M = 10, and MB = 8, then the mean number of coins for the girls is:

`10=0.6*8+0.4*M_G\\M_G=(10-4.8)/(0.4)\\M_G=13\ coins`

The mean number of coins for the girls is 13.