Please help i need help on question b

Mathematics

2 answers:

wolverine [178]3 years ago

5 0

Answer:

1500p or $15

Step-by-step 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

anzhelika [568]3 years ago

3 0

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

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Jacob can create an app in 24 hours, but if he works together with a friend they can create an app in 16 hours. How long would i

iogann1982 [59]

Answer:

Time taken by his friend to create the app alone = 48 hours.

Step-by-step explanation:

Hours needed by Jacob to create an app = 24 hours

$\text{One hour work of Jacob = }\frac{1}{24}$

Let hours needed by his friend in creating the app alone = x hours

$\text{So, one hour work of his friend = }\frac{1}{x}$

The both can create the app in 16 hours.

$\implies \frac{1}{24}+\frac{1}{x}=\frac{1}{16}\\\\\implies\frac{1}{x}=\frac{1}{16}-\frac{1}{24}\\\\\implies\frac{1}{x}=\frac{24-16}{24\times 16}\\\\\implies \frac{1}{x}=\frac{1}{48}\\\\\bf\implies x = 48$