Question

1. the number of books read by a student increased from 12 books last month to 18 books this month.

original value:
new value:
percent of change:

1. a store sold 200 items last week and only 150 items this week.

original value:
new value:
percent of change:

part c: real - life applications

1. a phone originally costs $600. during a sale, the price is reduced to $480.

a. is this an increase or decrease?
b. what is the percent of change?
show your work:

1. a student’s test score increases from 72 to 90.

a. is this an increase or decrease?
b. what is the percent of change?
show your work:

part d: challenge problems

1. the population of a town was 12,000 people. after one year, the population increased to 13,500.

percent of change:

Explanation:

First Problem (Books Read)

Step1: Identify Original and New Values

Original Value (last month) = 12, New Value (this month) = 18

Step2: Calculate Change

Change = New - Original = \( 18 - 12 = 6 \)

Step3: Percent of Change

Percent Change = \( \frac{\text{Change}}{\text{Original}} \times 100 = \frac{6}{12} \times 100 = 50\% \) (increase)

Step1: Identify Original and New Values

Original Value (last week) = 200, New Value (this week) = 150

Step2: Calculate Change

Change = New - Original = \( 150 - 200 = -50 \) (negative means decrease)

Step3: Percent of Change

Percent Change = \( \frac{\text{Change}}{\text{Original}} \times 100 = \frac{-50}{200} \times 100 = -25\% \) (or 25% decrease)

The original price is $600, and the new price is $480. Since \( 480 < 600 \), the price has decreased.

Answer:

Original Value: 12, New Value: 18, Percent of Change: 50% increase

Second Problem (Store Sales)