# Lesson 6

Increasing and Decreasing

Let’s use percentages to describe increases and decreases.

### Problem 1

For each diagram, decide if $$y$$ is an increase or a decrease relative to $$x$$. Then determine the percent increase or decrease.

### Problem 2

Draw diagrams to represent the following situations.

1. The amount of flour that the bakery used this month was a 50% increase relative to last month.
2. The amount of milk that the bakery used this month was a 75% decrease relative to last month.

### Problem 3

Write each percent increase or decrease as a percentage of the initial amount. The first one is done for you.

1. This year, there was 40% more snow than last year.

The amount of snow this year is 140% of the amount of snow last year.

2. This year, there were 25% fewer sunny days than last year.
3. Compared to last month, there was a 50% increase in the number of houses sold this month.
4. The runner’s time to complete the marathon was a 10% less than the time to complete the last marathon.

### Problem 4

The graph shows the relationship between the diameter and the circumference of a circle with the point $$(1,\pi)$$ shown. Find 3 more points that are on the line.

(From Unit 3, Lesson 3.)

### Problem 5

Priya bought $$x$$ grams of flour. Clare bought $$\frac38$$ more than that. Select all equations that represent the relationship between the amount of flour that Priya bought, $$x$$, and the amount of flour that Clare bought, $$y$$.

A:

$$y=\frac38 x$$

B:

$$y=\frac58 x$$

C:

$$y=x+\frac38x$$

D:

$$y=x -\frac38 x$$

E:

$$y=\frac{11}{8}x$$

(From Unit 4, Lesson 4.)