Unit 4, Lesson 7
One Hundred Percent
Grade 7
Practice
Problem 1
A city held a tree-planting event and increased the number of trees in their downtown area by 25%.
- Before the event, they had 48 trees. How many trees do they have now?
- Scientists have found that trees can make an area \(9^\circ\text{F}\) cooler. What percentage is this decrease if the peak summer temperature is usually \(90^\circ\text{F}\)?
Problem 2
A company has decreased the amount of plastic packaging on their product by 25%. If the packaging now weighs 48 grams, what did it weigh before the change?
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.
\(12+0.25 \boldcdot 12\)
\(12\left(1+0.25\right)\)
\(12 \boldcdot 1.25\)
\(12 \boldcdot 0.25\)
\(12 + 0.25\)
Problem 5
A circle’s circumference is 600 m. What is a good approximation of the circle’s area?
300 m2
3,000 m2
30,000 m2
300,000 m2
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.
- What does the number 3 represent?
- How many minutes does it take the snail to get 9 inches from the rock?
- How far will the snail be from the rock after 9 minutes?