This handy Spectrum Math Grade 7 Answer Key Chapter 7 Pretest provides detailed answers for the workbook questions

Check What You Know

Complete a frequency table using the following data.

Question 1.
Daily High Temperature (°F): 66, 68, 72, 79, 67, 82, 73, 85, 68, 81,73, 82, 69, 73, 74

Explanation:
Given from the frequency table by using the data completed the frequency ,cumulative frequency and relative frequency .

Use the spinner to determine the probability of the following events. Write your answer as a fraction in simplest form.

Question 2.
spinning a gray section ________________
$$\frac{1}{2}$$,

Explanation:
Given number of grey sections is 4 ,and no of outcomes is 8 so, spinning a grey section is 4/8 = 1/2.

Question 3.
spinning a 3 ________________
$$\frac{1}{8}$$,

Explanation:
Given number of 3 is 1 and no of outcomes is 8 so, the probability of spinning a 3 is 1/8.

Question 4.
spinning an even number ________________
$$\frac{5}{8}$$,

Explanation:
Given from spinner number of even numbers are 2,4,6,4,2 is 5 and no of outcomes is 8 so, the probability of spinning an even number is 5/8.

Question 5.
spinning a 2 ________________
$$\frac{1}{4}$$,

Explanation:
Given from the spinner the number of 2 is 2 and no of outcomes is 8 so, the probability of spinning a 2 is 1/4.

Color or label the shapes below so that the event will have uniform probability.

Question 6.
a.

Explanation;
Given from the figure the event has uniform probability.

b.

Explanation:
Given from the figure the event has uniform probability.

Question 7.
a.

Explanation:
Given from the figure the event has uniform probability.

b.

Explanation:
Given from the figure the event has uniform probability.

Solve the problems below.

Question 8.
A bag is full of marbles. There are 27 green marbles, 33 red marbles, and 12 blue marbles.

a. What is the probability of pulling out a red marble?
$$\frac{11}{24}$$,

Explanation:
Given no of red marbles P(R) is 33,and total no of  marbles in bag is P(G)+P(R)+P(B)=27+33+12=72 so, the probability of pulling out a red marble is 33/72=11/24.

b. What color is least likely to be pulled out of the bag?
Blue color,

Explanation:
Blue marbles is the least likely to be pulled out of the bag.

Question 9.
A spinner is split into 8 sections. Five sections are red, 2 sections are blue, and 1 section has a star on it.

a. What is the probability of landing on a blue section?
$$\frac{1}{4}$$,

Explanation:
Given total no of sections in spinner P(T) is 8 ,no of red sections P(R) are 5 , no .of blue sections P(B) are 2 and 1 section has star so, the probability of landing on a blue section is P(B)/P(T)=2/8=1/4.

b. What is the probability of landing on a red section?
$$\frac{5}{8}$$,

Explanation:
Given, the probability of landing on a red section is  P(R)/P(T)=5/8.

Question 10.
Monica’s closet has 9 shirts, 5 pairs of pants, and 4 pairs of shoes. How many combinations of outfits can she make that contain all 3 pieces of clothing?
Monica can make _____________ combinations of clothing.
Monica can make 180 combinations of clothing,

Explanation:
Given no of shirts are 9, no of pants are 5 pairs and no of shoes are 4 pairs so, Monica can make no of combinations are P(C)=9 X 5 X 4 = 180.

Create a tree diagram and then answer the questions.

Question 11.
Pepi’s Pizza has a choice of thin crust or thick crust. The available toppings are mushrooms, onions, pepperoni, and sausage. Make a tree diagram showing the possible outcomes for a 1 -topping pizza.

Explanation:
Given the available toppings are mushrooms ,onions, pepperoni and sausage which as shown in tree diagram of thin crust and thick crust.

Question 12.
How many possible outcomes are there?
Possible outcomes are 8,

Explanation:
Given from the tree diagram number of possible outcomes are 8.

Question 13.
What is the probability that the pizza will have thin crust?
$$\frac{1}{2}$$,

Explanation:
Given number of toppings of thin crust are 4 and number of outcomes are 8. So probability that the pizza will have thin crust is 4/8 = 1/2.

Question 14.
What is the probability that the pizza will have onions?
$$\frac{1}{4}$$,

Explanation:
Given number of onions in topping pizza is 2 and number of outcomes is 8. So, probability that the pizza has onions is 2/8 = 1/4.

Question 15.
What is the probability that the pizza will be thick crust and have mushrooms?
$$\frac{1}{8}$$,