Let’s solve each problem step by step.
---
Problem 1:
Ricardo has a spinner with 4 equal sections: red, yellow, blue, green.
So, probability of spinning
red = 1 out of 4 →
1/4
He also has a bag with:
- 2 red marbles
- 3 green marbles
- 3 blue marbles
Total marbles = 2 + 3 + 3 =
8
Probability of picking a
red marble = 2 out of 8 →
2/8 = 1/4
We want the probability that
both happen: spin red AND pick red marble.
Since these are independent events, we multiply:
→ (1/4) × (1/4) =
1/16
✔ Final Answer for Problem 1:
B. 1/16
---
Problem 2:
Bag has:
- Red marbles: let’s count from image — there are 3 red
- Blue marbles: 4 blue (from image)
Total = 3 + 4 =
7 marbles
First, pick a
blue marble: probability = 4/7
Then,
put it back → so total is still 7 marbles
Then, pick a
red marble: probability = 3/7
Multiply because both must happen in order:
→ (4/7) × (3/7)
Looking at options:
A. 4/7 × 4/7
B. 3/7 × 3/7
C. 4/7 × 3/6 ← wrong denominator, didn’t put back? But question says “putting it back”
D. 4/7 × 3/7 ← this matches!
✔ Final Answer for Problem 2:
D. 4/7 × 3/7
---
Problem 3:
Coin toss: two outcomes — heads or tails → P(tails) =
1/2
Number cube (die): numbers 1 to 6 → P(rolling a 3) =
1/6
We want both: coin shows tails AND die shows 3 → multiply probabilities:
→ (1/2) × (1/6) =
1/12
✔ Final Answer for Problem 3:
C. 1/12
---
Final Answers:
1. B
2. D
3. C
Parent Tip: Review the logic above to help your child master the concept of probability worksheet 3 compound events.
