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Probability, NAP-K4-CA37 SA

Cosette rolls a standard dice 100 times and records the results.

She calculates the experimental probability of rolling different numbers on this dice.

●   rolling an odd number 0.47
●   rolling a 4 0.15
●   not rolling a 6 0.88

 
What is the experimental probability of Cosette rolling a 2 on this dice?

 
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`0.26`

Show Worked Solution

`Ptext{(rolling 4)}= 0.15`

`Ptext{(rolling 1, 3 or 5)}= 0.47`

`Ptext{(rolling 6)}` `= 1 -Ptext{(not rolling 6)}`
  `= 1 – 0.88`
  `= 0.12`

 
`text(S) text(ince probabilities sum to 1,)`

`Ptext{(rolling 2)}` `= 1 – (0.47 + 0.15 + 0.12)`
  `= 0.26`

Probability, NAP-A4-NC24

Peter's fitness coach runs fitness drills so that the participants are exercising intensely for 20 seconds and then resting for 30 seconds.

What is the probability that Peter is resting at any single point in time during the session?

0.2 0.3 0.5 0.6
 
 
 
 
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`0.6`

Show Worked Solution
`P` `= text(time resting)/text(total time of session)`
  `= 30/(20+30)`
  `= 0.6`

Probability, NAP-D4-CA20

Sharney has a bag of 50 coloured marbles.

This table shows how many marbles of each colour are in the bag.
 

   
 
One marble is picked at random from the bag.

What is the probability of the marble being yellow or red?

`0.15` `0.20` `0.25` `0.30`
 
 
 
 
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`0.30`

Show Worked Solution

`text(Total of yellow and red marbles)`

`5 + 10 = 15`

`:.\ Ptext{(yellow or red)}` `=15/50`
  `=0.30`

Probability, NAP-E4-NC19 SA

Sharon made 24 milkshakes at her nephew's birthday party. Some were vanilla and some were chocolate.

All the milkshakes were served in an aluminium cup and looked the same.

Murray took one milkshake and had a 1 in 8 chance of taking a vanilla milkshake.

How many chocolate milkshakes did Sharon make?
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`21`

Show Worked Solution

`text(Number of vanilla)`

`= 1/8 xx 24`

`= 3`
 

`:.\ text(Number of chocolate)`

`= 24 – 3`

`= 21`

Probability, NAP-E4-NC12

Shane rolls a standard six-sided dice.

Which of the following events has a probability of less than  0.5?

 
 rolling a number greater than 1
 
 rolling an odd number
 
 rolling a number less than 6
 
 rolling a number greater than or equal to 6
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`text(rolling a number greater than or equal to 6)`

Show Worked Solution

`P(text(number) >= 6) = 1/6,`

`text(which is less than 0.5.)`