Probability, NAPX-K2-12

Question

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Worked Solution

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Variant 0

DifficultyLevel

438

Question

Eight buttons, numbered 1 to 8, are placed in a bag.

Robin picks three buttons out of the bag without looking.

Once chosen, a button is not put back into the bag.

The first button is number 2.

Which of the following cannot happen?

Worked Solution

Once number 2 is picked, it cannot be picked again (no replacement).

\therefore The third button cannot be 2.

Question Type

Multiple Choice (One Answer)

Variables

Variable nameVariable value
question
Eight buttons, numbered 1 to 8, are placed in a bag. Robin picks three buttons out of the bag without looking. Once chosen, a button is not put back into the bag. The first button is number 2. Which of the following cannot happen?
workedSolution
Once number 2 is picked, it cannot be picked again (no replacement). $\therefore$ The third button cannot be 2.
correctAnswer
The third button is 2.

Answers

Is Correct?Answer
x

The second button is even.

The third button is 2.

x

The second button is odd.

x

The third button is 8.


Variant 1

DifficultyLevel

441

Question

Six buttons, numbered 1 to 6, are placed in a bag.

Barney picks four buttons out of the bag without looking.

Once chosen, a button is not put back into the bag.

The first three buttons Barney chose, in order, are 5, 1 and 3.

Which of the following cannot happen?

Worked Solution

Once numbers 5, 3 and 1 are picked, they cannot be picked again (no replacement).

\therefore The 4th button chosen cannot be odd \rightarrow only even numbers left.

Question Type

Multiple Choice (One Answer)

Variables

Variable nameVariable value
question
Six buttons, numbered 1 to 6, are placed in a bag. Barney picks four buttons out of the bag without looking. Once chosen, a button is not put back into the bag. The first three buttons Barney chose, in order, are 5, 1 and 3. Which of the following cannot happen?
workedSolution
Once numbers 5, 3 and 1 are picked, they cannot be picked again (no replacement). $\therefore$ The 4th button chosen cannot be odd $\rightarrow$ only even numbers left.
correctAnswer
The 4th button chosen is odd.

Answers

Is Correct?Answer
x

The 4th button chosen is even.

x

The 4th button chosen is 6.

x

The 4th button chosen is 2.

The 4th button chosen is odd.


Variant 2

DifficultyLevel

439

Question

Seven buttons, numbered 1 to 7, are placed in a bag.

Zac picks four buttons out of the bag without looking.

Once chosen, a button is not put back into the bag.

The first two buttons Zac chose are 6 and 2.

Which of the following cannot happen?

Worked Solution

Once numbers 6 and 2 are picked, they cannot be picked again (no replacement).

\therefore The 3rd and 4th picks cannot both be even \rightarrow only one even number is left.

Question Type

Multiple Choice (One Answer)

Variables

Variable nameVariable value
question
Seven buttons, numbered 1 to 7, are placed in a bag. Zac picks four buttons out of the bag without looking. Once chosen, a button is not put back into the bag. The first two buttons Zac chose are 6 and 2. Which of the following cannot happen?
workedSolution
Once numbers 6 and 2 are picked, they cannot be picked again (no replacement). $\therefore$ The 3rd and 4th picks cannot both be even $\rightarrow$ only one even number is left.
correctAnswer
The 3rd and 4th pick can both be even.

Answers

Is Correct?Answer
x

The 3rd pick can be 4.

The 3rd and 4th pick can both be even.

x

The 4th pick can be 1.

x

The 3rd pick can be odd.

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