Excel in your academics by accessing McGraw Hill Math Grade 7 Answer Key PDF Lesson 23.3 Probability of Compound Events existing for free of cost.
McGraw-Hill Math Grade 7 Answer Key Lesson 23.3 Probability of Compound Events
Exercises
CALCULATE
Question 1.
Zane rolls a six-sided die twice. What is the probability that he will roll a 3 and then a 4?
Answer:
\(\frac{1}{36}\)
Explanation:
There is a formula to figure out probability (P)
It is the number of favorable out comes (f) divided by the total number of all possible outcomes (o).
In mathematical terms P = \(\frac{f}{o}\)
P = \(\frac{f}{o}\)
= \(\frac{1}{36}\)
Question 2.
Marisa draws a coin from a box that contains 7 quarters, 5 dimes, 10 nickels, and 8 pennies. After looking at the coin, she puts it back and draws another. What is the probability that the coins she drew were a dime and then a penny?
Answer:
\(\frac{2}{45}\)
Explanation:
There is a formula to figure out probability (P)
It is the number of favorable out comes (f) divided by the total number of all possible outcomes (o).
In mathematical terms P = \(\frac{f}{o}\)
a box that contains 7 quarters, 5 dimes, 10 nickels, and 8 pennies
7 + 5 + 10 + 8 = 30
P = \(\frac{f}{o}\)
= \(\frac{2}{45}\)
Question 3.
Mrs. Castanon chose two students’ names from a hat (she chose the second name without replacing the first name). There are 30 students in her class. What is the probability that she chose John and then Nicholle?
Answer:
\(\frac{1}{870}\)
Explanation:
Probability of choosing John = \(\frac{1}{30}\)
Remaining names of students in the hat = 30 – 1 = 29
Probability of choosing Nicholle = \(\frac{1}{29}\)
Total probability of choosing Jhon and Nicholle = \(\frac{1}{30}\) x \(\frac{1}{29}\)
The probability that Castanon chose John and then Nicholle = \(\frac{1}{870}\)
Question 4.
Lori and Sergio love lollipops. At the same time, they each take one lollipop from a bag containing 8 cherry, 4 orange, and 7 grape lollipops. What is the probability that they both got an orange one?
Answer:
\(\frac{2}{57}\)
Explanation:
Total number of lollipops = 8 + 4 + 7 = 19
Number of orange lollipops = 4
number of orange lollipops taken = 2
Probability of Lori choosing an orange lollipop = \(\frac{4}{19}\)
Remaining number of orange lollipops in the bag = 4 – 1 = 3
Probability of Lori choosing an orange lollipop = \(\frac{3}{18}\)
the probability that they both got an orange lollipop = \(\frac{4}{19}\) x \(\frac{3}{18}\)
= \(\frac{2}{57}\)
Question 5.
Kalee and Nick are choosing two different movies to watch. In their collection, they have 10 sci-fi movies, 12 comedies, and 5 dramas. If Kalee chooses the first movie at random and then Nick chooses the second movie at random, what is the probability that they both choose sci-fi movies?
Answer:
\(\frac{5}{39}\)
Explanation:
Total number of movies = 10 + 12 + 5 = 27
Number of sci-fi movies = 10
Probability of choosing an sci-fi movies = \(\frac{10}{27}\)
Remaining number of sci-fi movies = 10 – 1 = 9
Probability of choosing a sci-fi movie = \(\frac{9}{26}\)
the probability that they both got an orange lollipop = \(\frac{10}{27}\) x \(\frac{9}{26}\)
= \(\frac{5}{39}\)
Question 6.
Amee wants to make a simulation to help her find the probability that there will be one girl and one boy from her class chosen for student council, if two students in the class are chosen at random. How can she design her simulation?
Answer:
Answer may vary.
Explanation:
Probability is about estimating or calculating how likely or ‘probable’ something is to happen.
Amee should use black squares of paper to represent the number of boys,
and white squares of paper to represent the number of girls.