4MA0 Foundation January 2015 Paper 1 Q18

EdexcelFoundationOld spec7 marksBasic Probability

18 A jar contains 72 coloured beads.
There are 24 red beads, 28 blue beads and 20 green beads.

Ajit takes at random a bead from the jar.

(a) Find the probability that the bead Ajit takes is

(i) red,

(ii) blue or green.

(3)

A second jar contains coloured beads.
Ajit takes at random a bead from the jar.
The probability that the bead is yellow is 0.08
The probability that the bead is pink is 0.1

(b) Find the probability that the bead is neither yellow nor pink. (2)

A third jar contains 100 coloured beads.
20 of these beads are brown.
Ajit takes at random a bead from the jar.
He records the colour of the bead and then returns the bead to the jar.
He does this 60 times.

Mark scheme (a)

Scheme	Marks
(i) \(\dfrac{24}{72}\)	B1
(ii) 28 + 20 or 72 − 24 or 48 or \(1 - \text{“}\dfrac{24}{72}\text{”}\)	M1ft
\(\dfrac{48}{72}\)	A1ft
	(3)

Notes

B1: oe eg \(\dfrac{1}{3}\)

Accept 0.33(3333…) correct to at least 2dp

M1ft: ft from their (a)(i) if 0 < (a)(i) < 1

A1ft: oe eg \(\dfrac{2}{3}\)

Accept 0.66(66…..) rounded or truncated to at least 2 dp

ft from their (a)(i) if 0 < (a)(i) < 1

M1A0 for 48:72 oe

Scheme	Marks
\(\dfrac{20}{100} \times 60\) oe	M1
12	A1
	(2)
	(7 marks)