Data and charts · Ages 8–9

Probability: more or less likely worksheet

Part of: Chance and probability

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Data and charts · Ages 8–9

Numsprite
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Write each answer in the space. For word problems, show your working and write a sentence answer.

1.What is the fewest blue balls to put in so that red 🔴 and blue 🔵 become equally likely?
Answer:

2.A ball is taken from the bag without looking. Red 🔴 and blue 🔵 are equally likely.
True or false?
Answer:
3.Spin this spinner. Which colour is it least likely to land on?
- A. All three are equally likely
- B. Blue 🔵
- C. Yellow 🟡
- D. Red 🔴
Choose the right answer
Answer:
4.A ball is taken from the bag without looking. Which colour is it most likely to be?
- A. Yellow 🟡
- B. Red 🔴
- C. Green 🟢
- D. Blue 🔵
Choose the right answer
Answer:
5.Each bag holds 7 balls. From which bag is a ball taken without looking most likely to be red 🔴?
- A
- B
- C
- D
Choose the right picture
Answer:
6.A ball is taken without looking from bag A or bag B. Which bag gives a better chance of red 🔴?
- A. The chances are the same
- B. Bag A
- C. Bag B
- D. You can only tell by trying
Choose the right answer
Answer:
7.Each bag holds 8 balls. From which bag is a ball taken without looking most likely to be red 🔴?
- A
- B
- C
- D
Choose the right picture
Answer:

8.Chi-keung may choose bag A or bag B and take one ball without looking; a red ball wins. Bag A holds 6 red and 4 blue; bag B holds 4 red and 6 blue. Which bag should Chi-keung choose?
- A. It makes no difference
- B. Neither can win
- C. Bag B
- D. Bag A
Choose the right answer
Working:
Answer:
9.A box holds 4 milk, 2 dark and 9 white chocolates that all look the same. Ka-yee takes one without looking. Which kind is it most likely to be?
- A. White
- B. Dark
- C. Milk
- D. Nut
Choose the right answer
Working:
Answer:
10.A spinner has 8 equal parts, each painted red or blue. For red to be more likely than blue, what is the fewest parts that must be red?
Working:
Answer:
11.Chi-keung's game stall has a bag holding 9 red and 9 blue balls, and a blue ball wins a prize. Chi-keung wants blue to be more likely than red. What is the fewest blue balls Chi-keung must put in?
Working:
Answer:
12.A box holds 6 milk, 2 dark and 8 white chocolates that all look the same. Chi-keung takes one without looking. Which kind is it most likely to be?
- A. Nut
- B. Milk
- C. Dark
- D. White
Choose the right answer
Working:
Answer:
13.Ka-yan may choose bag A or bag B and take one ball without looking; a red ball wins. Bag A holds 1 red and 6 blue; bag B holds 2 red and 5 blue. Which bag should Ka-yan choose?
- A. Neither can win
- B. It makes no difference
- C. Bag A
- D. Bag B
Choose the right answer
Working:
Answer:

Show the answers and working

Probability: more or less likely worksheet: Answers and working

1. 4
Count the red and blue balls first. For equal chances, there must be the same number of each.
The bag has 8 red and 4 blue. Equal chances need equal numbers: put in 8 − 4 = 4 blue.

2. False
Count the red and the blue balls, and check whether there are the same number.
Count: 3 red, 1 blue. Only the same number gives the same chance.
3. D. Red 🔴
The parts are the same size, so count how many parts each colour has and compare.
The parts are equal, so count them: red 1, blue 3, yellow 4. The colour with the fewest parts is least likely.
4. D. Blue 🔵
Count the balls of each colour, then see which has the most.
Count: 4 red, 7 blue, 3 yellow. The colour with the most balls is the most likely.
5. C
Every bag holds 7 balls, so just count the red in each bag and compare.
Every bag holds the same number, so the bag with the most red (6) gives the best chance.
6. B. Bag A
Count the red and blue in both bags. With the same red, see which bag has fewer blue.
Both bags have 2 red; the bag with fewer blue balls has red as a bigger share: A has 1 blue, B has 5.
7. C
Every bag holds 8 balls, so just count the red in each bag and compare.
Every bag holds the same number, so the bag with the most red (7) gives the best chance.

Marking: 2 for the working, 1 for the answer, 1 for the sentence.

8. D. Bag A
Do the two bags hold the same number of balls? Find each bag's total first, then compare the red.
Both bags hold 10 balls, so the one with more red is better: compare 6 and 4.
9. A. White
Compare the three numbers 4, 2 and 9: which kind is there most of?
The kind with the biggest number of 4, 2 and 9 is the most likely.
10. 5 parts
Red must beat blue, so it needs more than half of the 8 parts. Think what half of 8 is first.
Red must outnumber blue, so more than half of the 8: at least 5 red (3 blue).
11. 1 ball
Blue must outnumber the 9 red. What is the least blue there can be? There are 9 already.
Blue must outnumber red: at least 9 + 1 blue, so put in 9 + 1 − 9 = 1.
12. D. White
Compare the three numbers 6, 2 and 8: which kind is there most of?
The kind with the biggest number of 6, 2 and 8 is the most likely.
13. D. Bag B
Do the two bags hold the same number of balls? Find each bag's total first, then compare the red.
Both bags hold 7 balls, so the one with more red is better: compare 1 and 2.

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