Use a simulation to estimate a compound chance

Answer Key - Grade 8 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Bo's bus is late 20% of days, and it rains 40% of days. Bo copies one day with 2 random digits: the first for the bus, the second for rain. Which plan works?

   • Bus: 0 and 1 mean late. Rain: 0 to 3 mean rain.
   • Bus and rain: 0 to 3 mean yes for both
   • Bus: 0 to 2 mean late. Rain: 0 to 4 mean rain, counting the end digits.

2. Read this first

   Use this

   0 to 6 is a make; 7 to 9 is a miss. Two digits make one try. Digits, 2 per try: 2059 1066 5709 3576 5792.

3. 2.

   Jun makes 70% of free throws and copies 2 shots with random digits. In how many of these 10 tries are both shots makes?

   4

4. Use this

   0 to 3 is gold; 4 to 9 is not. Two digits make one try. Digits, 2 per try: 4777 2240 9498 8039 8029.

5. 3.

   Kira's spinner has 10 equal parts, and 4 are gold. Kira copies 2 spins with random digits. In how many of these 10 tries is at least one spin gold?

   6

6. First digit

   0 and 1 mean the bus is late. Second digit: 0 to 3 mean rain. Digits, 2 per try: 0947 2260 7741 6926 8202.

7. 4.

   Luz's bus is late 20% of days, and it rains 40% of days. Luz copies 10 days with random digits. On how many days is the bus late, it rains, or both?

   6

8. Use this

   0 to 5 is a sprout; 6 to 9 is not. Two digits make one try. Digits, 2 per try: 6486 1526 8428 7315 6604.

9. 5.

   A seed sprouts 60% of the time. Milo copies planting 2 seeds with random digits. In how many of these 10 tries do both seeds sprout?

   3

10. Use this

    0 to 6 is a make; 7 to 9 is a miss. Two digits make one try. Tries: 10, 40, 22, 43, 99, 39, 60, 02, 84, 08.

11. 6.

    Noah makes 70% of free throws and copies 2 shots with random digits. From these 10 tries, what is the estimated chance both shots are makes, in simplest form?

    3/5

12. Use this

    0 to 5 is a sprout; 6 to 9 is not. Two digits make one try. Tries: 57, 87, 02, 54, 35, 76, 73, 74, 84, 48.

13. 7.

    A seed sprouts 60% of the time. Pia copies planting 2 seeds with random digits. From these 10 tries, what is the estimated chance at least one sprouts, in simplest form?

    4/5

14. Use this

    0 to 2 is gold; 3 to 9 is not. Two digits make one try. Tries: 21, 21, 03, 89, 83, 52, 06, 14, 47, 64.

15. 8.

    Ren's spinner has 10 equal parts, and 3 are gold. Ren copies 2 spins with random digits. From these 10 tries, what is the estimated chance of at least one gold?

    3/5

16. First digit

    0 and 1 mean the bus is late. Second digit: 0 to 3 mean rain. Tries: 83, 35, 01, 98, 22, 01, 59, 66, 12, 03.

17. 9.

    Tala's bus is late 20% of days, and it rains 40% of days. From these 10 copied days, what is the estimated chance of a late bus, rain, or both?

    3/5

18. Use this

    0 to 4 is a goal; 5 to 9 is a miss. Two digits make one try. Tries: 46, 85, 07, 98, 54, 87, 89, 76, 22, 08.

19. 10.

    Zee scores on 50% of penalty kicks and copies 2 kicks with random digits. From these 10 tries, what is the estimated chance both are goals?

    1/10