Name: _________________
Math 7 accel.
WORKSHEET: Compound Probability
Feb. 27, 2012
Problems 1 – 4: Write all probabilities & odds as simplified fraction or ratio.
A jar contains four flavors of jellybeans in the following quantities:
 16 - lemon
 14 - pomegranate
 12 - watermelon
 8 - coffee
1. You choose one jellybean at random from the jar. Find the probability of:
a. choosing a watermelon jellybean
b. not choosing a pomegranate jellybean
2. You choose one jellybean at random from the jar. Find the odds of:
c. choosing a lemon jellybean
d. choosing a coffee or pomegranate jellybean
3. You choose two jellybeans from the jar, with replacement. Find the probability of:
e. choosing two coffee jellybeans
f. choosing lemon followed by pomegranate
g. not choosing a watermelon jellybean
4. You choose two jellybeans from jar, without replacement. Find the probability of:
h. choosing two coffee jellybeans
j. choosing pomegranate followed by lemon
i. choosing lemon followed by pomegranate
Problems 5 - 7:
Cards are dealt from a standard deck of playing cards (no jokers):
5. Two cards are dealt, with replacement. What is the probability that
a. you deal an ace followed by a king
b. you deal two spades
6. Two cards are dealt, without replacement. What is the probability that you deal
c. two aces
d. a red queen followed by a club
e. a red queen followed by a diamond
7. Three cards are dealt, without replacement. What is the probability that you deal
f. three kings
g. a jack, a queen, and a king (in that order)
h. a jack, a queen, and a king (in any order)
8. A basketball player makes 72% of her free throws.
a. What are her odds of making a free throw?
b. What is the probability that she will sink three straight free throws?
c. What is the probability that she will miss two free throws and then make one.
9. Each evening, Joe’s BBQ offers, at random, one free dinner to a lucky diner. On Friday night, Joe has
120 customers, and on Saturday, Joe has 150 customers. What are your odds of winning both nights?
10. You toss a coin. What is the probability that you get heads 7 times in a row? If you’ve already tossed
the coin six times and gotten heads each time, what is the probability that you will get heads the 7th time?
11. You toss a coin ten times. What is the probability that you get exactly 5 heads? What is the
probability that you get at least one heads? What is the probability that you get at least 5 heads?
12. What is the probability of rolling “snake eyes” (double ones) three times in a row with a pair of dice?
13. Jar A contains 3 red balls and 4 white balls. Jar B contains 5 red balls and 2 white balls. Which of the
following ways of randomly selecting balls gives the greatest probability of drawing 2 red balls?
(i) Draw two balls from Jar A
(ii) Draw one ball from each jar
(iii) Put the balls in one jar and then draw two balls
14. What is the probability that, in a group of 6 people, at least two of them will have the same birthday?
15. What is the smallest size group for which the probability of at least two people having the same
birthday is greater than 50%?