Lesson 1: Practice Problems

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:

• yes

• yes

• yes

• no

• no

• no

• no

• no

• no

• no

• yes

• no

• no

• no

If she asks one more person randomly in the cafeteria, do you think they will say “yes” or “no”? Explain your reasoning.

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:

• 1,200

• 1,400

• 1,300

• 1,500

• 950

• 1,600

• 1,100

Do you think that this material will be able to hold more than 1,000 pounds in the next test? Explain your reasoning.

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.

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?