Two-step chance: lists, tables and trees

Answer Key - Grade 7 Math Worksheet

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

1. 1.

   Esme rolls a fair number cube and flips a fair coin. What is the chance of a number 4 or greater and heads, in simplest form?

   1/4
2. 2.

   Luz flips a fair coin and spins a spinner with 4 equal parts numbered 1 to 4. What is the chance of heads and a 4, as a percent?

   12.5
3. 3.

   Milo flips two fair coins. What is the chance of two heads, as a percent?

   25
4. 4.

   Noah draws one of 5 cards numbered 1 to 5 without looking and flips a fair coin. What is the chance of a card showing 1 or 5, and heads, as a percent?

   20
5. 5.

   Tala rolls two fair number cubes. What is the chance that the sum is 9, in simplest form?

   1/9
6. 6.

   Bo flips two fair coins. What is the chance of at least one head, in simplest form?

   3/4
7. 7.

   Esme spins two spinners, each with 4 equal parts: red, blue, green, yellow. What is the chance that the two colors are different, in simplest form?

   3/4
8. 8.

   Kira spins two spinners, each with 3 equal parts: red (R), blue (B), green (G). Which is the whole list of outcomes for both spinners?

   • RR, RB, RG, BR, BB, BG, GR, GB, GG
   • R, B, G
   • RR, RB, RG, BB, BG, GG
   • RR, RB, RG, BR, BB, BG, GR, GB

9. Read this first

   Tree

   The spinner splits into 1, 2 and 3; each of those splits into H and T. Leaves: 1-H, 1-T, 2-H, 2-T, 3-H, 3-T.

10. 9.

    Noah spins a spinner with 3 equal parts numbered 1 to 3, then flips a fair coin, as the tree shows. What is the chance of an odd number and tails, in simplest form?

    1/3

11. Tree

    The card splits into red and blue; each of those splits into 1, 2, 3 and 4. Leaves: red-1, red-2, red-3, red-4, blue-1, blue-2, blue-3, blue-4.

12. 10.

    Pia picks 1 of 2 cards (1 red, 1 blue) without looking, then spins a spinner (1 to 4, equal parts). What is the chance of blue and a number over 2, in simplest form?

    1/4