4400 Higher November 2007 Paper 4 Q24

EdexcelHigherOld spec3 marksMultiple Events

Box A with 3 black and 2 white counters; Box B with 2 black and 1 white counter

In Box A, there are 3 black counters and 2 white counters.
In Box B, there are 2 black counters and 1 white counter.
Farah takes at random a counter from Box A and puts it in Box B.
She then takes at random a counter from Box B.
Work out the probability that the counter she takes from Box B will be a black counter.

(3)

Scheme	Marks
\(\frac{3}{5} \times \frac{3}{4} + \frac{2}{5} \times \frac{2}{4}\)	M2
\(\dfrac{13}{20}\)	A1
	(3)
	(3 marks)

Notes