Question

Plz can you help me out with this question..

Answer 1

86%

Explanation:

The mean is calculated as

mean =
`(sum)/(count)`

The sum for the class is calculated as

`(sum)/(30)` = 70 ( multiply both sides by 30 )

sum = 2100

The sum of the 20 boys is

`(sum)/(20)` = 62 ( multiply both sides by 20 )

sum = 1240

The sum for the 10 girls is therefore 2100 - 1240 = 860

Thus the mean mark for the girls is

mean =
`(860)/(10)` = 86%