1MA0 Higher November 2016 Paper 1 Q16
16 There are 15 children at a birthday party.
The mean age of the 15 children is 7 years.
9 of the 15 children are boys.
The mean age of the boys is 5 years.
Work out the mean age of the girls. (3)
| Answer | Mark | Notes |
|---|---|---|
| 10 | 3 | M1 for \(15 \times 7\) (= 105) or \(9 \times 5\) (= 45) M1 for \((15 \times 7 - 9 \times 5) \div (15 - 9)\) A1 cao |