Foundation June 2018 Paper 3 Q9
9 A music app has a shuffle play function.
This means that songs are played in a random order without repeat.
(a) Ruth puts 10 songs on shuffle play.
One of them is her favourite song.
Write down the probability that her favourite song plays first. [1 mark]
(b) Ted puts songs A, B and C on shuffle play.
List all the possible orders of songs A, B and C.
One has been done for you. [2 marks]
A B C
| Answer | Mark | Comments |
|---|---|---|
| \(\dfrac{1}{10}\) or 0.1(0) or 10% | B1 | oe |
Additional guidance
| Ignore further working with any description of probability eg \(\dfrac{1}{10}\), unlikely | B1 |
| Ignore further working with attempt to simplify a correct fraction eg \(\dfrac{10}{100} = \dfrac{5}{20}\) | B1 |
| 1 : 10 in working with \(\dfrac{1}{10}\) on answer line | B1 |
| 1 : 10 on answer line | B0 |
| 1 out of 10 without \(\dfrac{1}{10}\) in working | B0 |
| Answer | Mark | Comments |
|---|---|---|
| (ABC) BAC CAB ACB BCA CBA | B2 | Any order B1 for four additional correct orders with no errors or repetitions or five additional correct orders with at most one error or repetition |
Additional guidance
Do not allow repetition of ABC for B2