Grade 7 Mathematics: Open Up Resources, Common Core State Standards Edition

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Chapter 8

Probability and Sampling - all with Video Answers

Educators

Section 1

Mystery Bags

Problem 1

Lin is interested in how many of her classmates watch her favorite TV show, so she starts asking around at lunch. She gets the following responses:
$$
\begin{array}{|c|c|c|c|c|c|c|}
\hline \text { yes } & \text { yes } & \text { yes } & \text { no } & \text { no } & \text { no } & \text { no } \\
\hline \text { no } & \text { no } & \text { no } & \text { yes } & \text { no } & \text { no } & \text { no } \\
\hline
\end{array}
$$
If she asks one more person randomly in the cafeteria, do you think they will say "yes" or "no"? Explain your reasoning.

Allison Knapp

Allison Knapp

Numerade Educator

Problem 2

An engineer tests the strength of a new material by seeing how much weight it can hold before breaking. Previous tests have held these weights in pounds:
$$
\begin{array}{|l|l|l|l|l|l|l|}
\hline 1,200 & 1,400 & 1,300 & 1,500 & 950 & 1,600 & 1,100 \\
\hline
\end{array}
$$
Do you think that this material will be able to hold more than 1,000 pounds in the next test? Explain your reasoning.

Allison Knapp

Numerade Educator

Problem 3

A company tests two new products to make sure they last for more than a year.
- Product 1 had 950 out of 1,000 test items last for more than a year.
- Product 2 had 150 out of 200 last for more than a year.
If you had to choose one of these two products to use for more than a year, which one is more likely to last? Explain your reasoning.

Allison Knapp

Numerade Educator

Problem 4

Put these numbers in order from least to greatest.
a. $\frac{1}{2}$
b. $\frac{1}{3}$
c. $\frac{2}{5}$
d. $0.6$
e. $0.3$

Allison Knapp

Numerade Educator

Problem 5

A small staircase is made so that the horizontal piece of each step is 10 inches long and 25 inches wide. Each step is 5 inches above the previous one. What is the surface area of this staircase?

Allison Knapp

Numerade Educator

Problem 6

Summary Lesson: Mystery Bags

Allison Knapp

Numerade Educator