1. The school is having a fundraising draw. First prize is meal for four at a local restaurant. There are 200 tickets sold. Sol buys 4 tickets. What is the probability of him winning the first prize?
Probability = 4/200 = 0.02
2. If you rolled a dice 24 times, how many times would you expect to roll a six?
Probability of a six = 1/6
Probability x number of rolls = 1/6 x 24 = 4
A six would be expected 4 times.
3. If you rolled a dice 48 times, how many times would you predict not to roll a six?
Probability of a six = 1/6. Probability of not rolling a six = 1  1/6 = 5/6
Probability x number of rolls = 5/6 x 48 = 40
A six would not be expected on 40 rolls of the dice.
4. If you rolled a dice 96 times, how many times would you expect to roll a three or a six?
Probability of a three or a six = 2/6
Probability x number of rolls = 2/6 x 96 = 32
A three or a six would be expected 32 times.
5. The local weather forecaster says she can predict whether it will rain with 80% accuracy which is equivalent to a 0.8 chance of being correct. If she forecasts rain 160 times, how many of these times would you expect she is wrong?
Probability of being wrong = 1  Probability of being correct = 1  0.8 = 0.2
Probability x number of forecasts = 0.2 x 160 = 32
It would be expected that she is wrong 32 times.
