Practice quiz answers using a tree diagram
Suppose that you have a bag with 4 green chips and 3 yellow chips.
1. If you choose two chips with replacement (you put the first chip back in
the bag before drawing the second chip),
A. What is the probability that you will get two greens?
B. What is the probability that you will get two yellows?
C . What is the probability that you will get one of each color?
With replacement probabilities:
Prob of getting green on first pick: |
Prob of getting another green if the first one is green: 4 greens out of 7 chips 4/7 |
Prob of getting a yellow if the first one is green 3 yellow out of 7 chips 3/7 |
| Prob of getting yellow on first pick 3 yellow out of 7 chips 3/7 |
Prob of getting green if the first one is yellow: 4 greens out of 7 chips 4/7 |
Prob of getting another yellow if the first one is yellow: 3 yellow out of 7 chips 3/7 |
(these fractions can't be simplified)
2. If you choose two chips without replacement (you keep the first chip out
of the bag while drawing the second chip),
A. What is the probability that you will get two greens?
B. What is the probability that you will get two yellows?
C . What is the probability that you will get one of each color?
Prob of getting green on first pick: |
Prob of getting another green if the first one is green: 3 greens out of 6 chips 3/6 |
Prob of getting a yellow if the first one is green 3 yellow out of 6 chips 3/6 |
| Prob of getting yellow on first pick 3 yellow out of 7 chips 3/7 |
Prob of getting green if the first one is yellow: 4 greens out of 6 chips 4/6 |
Prob of getting another yellow if the first one is yellow: 2 yellow out of 6 chips 2/6 |
Do more practice with tree diagrams: With replacement / without replacement
Read an explanation of where the numbers come from With replacement / without replacement