Big Ideas Math: Modeling Real Life, Grade 7
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Big Ideas Math: Modeling Real Life, Grade 7 View details
4. Percents of Increase and Decrease
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Exercise 25 Page 258

Is the value of the new amount greater than or less than the value of the original amount?

Increase or Decrease? Decrease
Percent of Change: 25 %

Practice makes perfect

We want to tell whether each percent change is an increase or decrease. Then, we want to find the percent change. Let's do it one at a time.

Percent Increase or Percent Decrease

Recall that if a new amount is greater than the original amount, the percent change is called a percent increase. If the new amount is less than the original amount, the percent change is called a percent decrease. Consider the given amounts. Original Amount:&4/5 [0.7em] New Amount:& 3/5We can see that the new amount is less than the original amount because the fractions have the same denominator and the numerator of the first fraction is greater. 4/5 > 3/5 ⇔ 4 > 5 As a result, the percent change is a decrease.

Finding the Percent Change

To determine the percent change p, we can use the following general formula. p % =Amount of change/Original amount From the given values, we can see the original amount was 45 and the new amount is 35. This is a decrease in the amount. Let's find the amount of decrease. 4/5- 3/5= 4-3/5 or 1/5 The difference between the original amount and the new amount is 15. Now we can use the formula.

Percent of change=Amount of decrease/Original amount
Percent of change=15/45
Percent of change=1/4
Percent of change=0.25
Percent of change = 25 %

The percent decrease is 25 %.