Foundation November 2019 Paper 1 Q18
18 Mo played 30 games of chess.
He won 18 of these games.
(a) What fraction of the games did he win?
Give your answer in its simplest form. [2 marks]
(b) He played 20 more games.
He had then won 64% of all of his games.
How many of the 20 games did he win? [3 marks]
| Answer | Mark | Comments |
|---|---|---|
| \(\dfrac{3}{5}\) | B2 | B1 \(\dfrac{18}{30}\) or \(\dfrac{9}{15}\) or \(\dfrac{6}{10}\) or 0.6(0) or 60% SC1 \(\dfrac{2}{5}\) |
Additional guidance
| \(\dfrac{18}{30}\) or \(\dfrac{9}{15}\) or \(\dfrac{6}{10}\) followed by incorrect simplification or any conversion | B1 |
| Answer | Mark | Comments |
|---|---|---|
| \(\dfrac{64}{100} \times (30 + 20)\) | M1 | oe eg \(0.64 \times 50\) or \(64 \div 2\) build up method must be complete |
| 32 | A1 | |
| 14 (out of 20) | A1ft | ft their 32 − 18 with M1A0 scored their 32 must be greater than 18 SC1 12.8 (or 13 after 12.8 is seen) |
Additional guidance
| \(\dfrac{14}{20}\) or 70% | M1A1A0 |
| 14 = 70% on answer line | M1A1A1 |
| Answer 32 or \(\dfrac{32}{50}\) | M1A1A0 |
| \(64\% \times 50\) with no further work | M0 |
| \(\dfrac{64}{100} \times 50 = 30\) Answer 12 | M1A0A1ft |
| Example of complete build-up (for 64% of 50) 10% = 5 (no working but correct) \(6 \times 5 = 30\) (correct with working) 1% = 0.5 (no working but correct) \(4 \times 0.5 = 0.20\) (incorrect but working shown so still on for M1) = 30.20 (implied correct addition) then 30.20 − 18 = 12.20 Answer 12.20 (condone decimal value for ft) | M1A0A1ft |
| Example of incomplete build-up (for 64% of 50) 50% = 25 (no working but correct) 10% = 5 (no working but correct) 2% = 2 (incorrect and no working shown M0) ……… (A0ft cannot award ft when M1 not awarded) | M0A0A0 |