Question

1.In a class of 45 pupils ,21play chess and 23 play cards and 5play both games

(a) find:
i. how many do not play any of the games .

ii. how many play chess only.
iii. how many play cards only .
(b). What is the probability of selecting a pupil who plays only one game?​

Answer 1

Explanation:

(a)

ii.

21 - 5 = 16 play only chess.

iii.

23 - 5 = 18 play only cards

5 play both.

that is 16+18+5 = 39 that play at least one of these games.

i.

so, 45 - 39 = 6 don't play any of these games.

(b)

we have 16+18 = 34 pupils out of 45 that play exactly one game.

so the probabilty to pick one of them is as usual

desired cases / total cases = 34/45 =

= 0.755555555... ≈ 0.76