Higher November 2019 Paper 2 Q3
3 Tom and Adam have a total of 240 stamps.
The ratio of the number of Tom’s stamps to the number of Adam’s stamps is \(3 : 7\)
Tom buys some stamps from Adam.
The ratio of the number of Tom’s stamps to the number of Adam’s stamps is now \(3 : 5\)
How many stamps does Tom buy from Adam?
You must show all your working. (4)
| Answer | Mark | Mark scheme |
|---|---|---|
| 18 | P1 | for \(240 \div 10\ (= 24)\) or \(240 \div 8\ (= 30)\) |
| P1 | for \(3 \times \text{``}24\text{''}\ (= 72)\) or \(7 \times \text{``}24\text{''}\ (= 168)\) or \(3 \times \text{``}30\text{''}\ (= 90)\) or \(5 \times \text{``}30\text{''}\ (= 150)\) | |
| P1 | for \(3 \times \text{``}24\text{''}\ (= 72)\) and \(3 \times \text{``}30\text{''}\ (= 90)\) or \(7 \times \text{``}24\text{''}\ (= 168)\) and \(5 \times \text{``}30\text{''}\ (= 150)\) | |
| A1 | Cao |
Additional guidance
Accept \(3 + 7\) for 10, \(3 + 5\) for 8