Home / IB DP Math AA: Topic: SL 4.5: The complementary events A and A′ (not A): IB Style Questions HL Paper 2

IB DP Math AA: Topic: SL 4.5: The complementary events A and A′ (not A): IB Style Questions HL Paper 2

Question

A team of 6 players is to be selected from 10 volleyball players, of whom 8 are boys and 2 are girls.

a.In how many ways can the team be selected?[2]

 

b.In how many of these selections is exactly one girl in the team?[3]

 

c.If the selection of the team is made at random, find the probability that exactly one girl is in the team.[2]

 
Answer/Explanation

Markscheme

\(\left( {\begin{array}{*{20}{c}}
  {10} \\
  6
\end{array}} \right) = 210\)     (M1)A1

[2 marks]

a.

\(2 \times \left( {\begin{array}{*{20}{c}}
  8 \\
  5
\end{array}} \right) = 112\)     (M1)A1A1

 Note: Accept \(210 – 28 – 70 = 112\)

 

[3 marks]

b.

\(\frac{{112}}{{210}}\,\,\left( { = \frac{8}{{15}} = 0.533} \right)\)     (M1)A1

[2 marks]

Scroll to Top