Lesson 7

One Hundred Percent

Problem 1

A bakery used 25% more butter this month than last month. If the bakery used 240 kilograms of butter last month, how much did it use this month?

Problem 2

Last week, the price of oranges at the farmer's market was \$1.75 per pound. This week, the price has decreased by 20%. What is the price of oranges this week?

Problem 3

Noah thinks the answers to these two questions will be the same. Do you agree with him? Explain your reasoning.

• This year, a herd of bison had a 10% increase in population. If there were 550 bison in the herd last year, how many are in the herd this year?
• This year, another herd of bison had a 10% decrease in population. If there are 550 bison in the herd this year, how many bison were there last year?

Problem 4

Elena walked 12 miles. Then she walked 0.25 that distance.  How far did she walk all together?  Select all that apply.

A:

$$12+0.25 \boldcdot 12$$

B:

$$12\left(1+0.25\right)$$

C:

$$12 \boldcdot 1.25$$

D:

$$12 \boldcdot 0.25$$

E:

$$12 + 0.25$$

Solution

(From Unit 4, Lesson 5.)

Problem 5

A circle’s circumference is 600 m. What is a good approximation of the circle’s area?

A:

300 m2

B:

3,000 m2

C:

30,000 m2

D:

300,000 m2

Solution

(From Unit 3, Lesson 8.)

Problem 6

The equation $$d = 3t$$ represents the relationship between the distance ($$d$$) in inches that a snail is from a certain rock and the time ($$t$$) in minutes.

1. What does the number 3 represent?
2. How many minutes does it take the snail to get 9 inches from the rock?
3. How far will the snail be from the rock after 9 minutes?