Question

Please help i need help on question b

Answer 1

1500p or $15

Explanation:

School either earns 20,

or loses 10 (20 - 30 = -10)

P(-10) = P(score is 7) = 3/12 = 1/4

P(20) = P(not a 7) = 1 - 1/4 = 3/4

Expected gain each game:

(-10)(1/4) + (20)(3/4)

12.5

If 120 games:

120 × 12.5

1500p

$15

Answer 2

There are 12 possible outcomes.....three of these will be a "7" ...so...

A "7" should occur 1/4 of the time

If each player pays 20p to play.....the school will take in 120 * 20 = 2400p

However.......1/4 of the players should win = 30 players.....and each lollipop costs 30p.....so......the school should spend 30 * 30 = 900p for the prizes

So......the school should raise 2400 - 900 = 1500p if 120 people play the game