4MA0 Higher January 2015 Paper 3 Q5

EdexcelHigherOld spec8 marksBasic Probability Multiple Events

5 A 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
The probability that the bead is blue is 0.25

(a)

(i) Find the probability that the bead is yellow or blue.

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

(4)

Ajit replaces the first bead in the jar.
He then takes at random a second bead from the jar.

(b) Find the probability that the first bead is yellow and the second bead is blue. (2)

A second 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) 0.08 + 0.25	M1
0.33	A1
(ii) 1 – 0.08 – 0.1 or 1 – (0.25 + 0.1 + 0.08) + 0.25 or 0.57 + 0.25 or (1 – (“0.33” + 0.1)) + 0.25	M1
0.82	A1
	(4)

Notes

A1: oe e.g. accept 33/100 0.33/1

M1: ft if their answer to (a)(i) is 0 < (a)(i) < 1

A1: oe eg accept 82/100
ft for 0 < answer < 1

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