Basic Probability: WJEC GCSE Intermediate November 2020 Unit 2 Q4

Intermediate November 2020 Unit 2 Q4

Yellow

WJECIntermediateCurrent spec4 marksBasic Probability Combinations

4. A game uses 15 coloured cards.
There are:

5 red (R) cards numbered 1 to 5,
5 yellow (Y) cards numbered 1 to 5,
5 pink (P) cards numbered 1 to 5.

The cards are all placed in a box.
One card is chosen at random from the box.

(a) The grid below is used to show all the possible outcomes.
Fill in all the spaces with a label or an outcome.
Some of the spaces have already been filled in. [2]

Outcome grid: Number across the top with five blank label cells; Colour down the side with two blank labels and Pink; Y3 filled in

(b) What is the probability that the card chosen at random is a pink card showing a number greater than 3? [2]

Mark scheme (a)

Scheme

Marks

Comments

All labels correctly inserted

Must be inserted in the table and not simply inferred from the outcomes.

Accept ‘R’ for Red and ‘Y’ for Yellow.

All outcomes correctly inserted

Allow ‘Red’ for ‘R’ etc.
Allow ‘1R’ for ‘R1’ etc.

Mark scheme (b)

Scheme	Marks	Comments
\(\dfrac{2}{15}\) or equivalent ISW.	B2	(No FT from an incorrect grid in 4a) B1 for a numerator of 2 in a fraction < 1. B1 for a denominator of 15 in a fraction < 1. Allow B2 for 0·13… Penalise −1 for incorrect notation eg ‘2 out of 15’, ‘2 : 15’ etc.