The ratio of the number of boys to the number of girls in the class is 1:6. Which statement must describe the class?
2 answers:
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Answer:
The school will approximately raise 1500p.
Step-by-step explanation:
For part a) you're asked to complete the possibility space, this simply means to fill out in the provided chart with all possible outcomes for spinning the two spinners and adding the result of each.
You are already given two examples, particularly the case of landing a 2 and 1 (hence you get a 3) and landing a 8 and 3 (hence you get an 11). Just finish filling up the chart per the examples.
For part b) we must calculate the probability of having the outcome be 7. Assuming all sides of both spinners have the same probability of landing, we calculate this using classical probability so, as follows:
Where represents the probability of getting seven,
the number of ways the two spinners can land in which they add up to 7, and
the number of all possible outcomes from spinning the two spinners. We are just doing the rule of "all favorable outcomes over all outcomes".
The total number of outcomes is 12, as there's only 12 ways the two spinners could land. The total number of ways we can get 7 is 3 (only by spinning 1 and 6, or 2 and 5, or 3 and 4). So, the probability of landing 7 is:
So, there's a 25% chance of getting a 7 (hence of winning at this game). This means, if 120 play, approximately a 25% of them will win - so, approximately 30 contestants will win.
The school is charging 20p for playing, so the 120 participants are paying 2400p. However, because approximately 30 people will win, the school will have to buy 30 lollipops that cost 30p each - so, at the end the school will raise approximately 2400p (total earnings of tickets) - 900p (total losses from people winning) = 1500p (total money raised).