Basic Mathematics for College Students

542 Chapter 6 Percent

To isolate xon the right side, divide both

sides of the equation by 5,000. Then

remove the common factor of 5,000

from the numerator and denominator.

Before performing the division on the left side of the equation, recall

that there is a shortcut for dividing a dividend by a divisor when both

end with zeros.

Remove the three ending zeros in the

divisor 5,000 and remove the same number

of ending zeros in the dividend 44,850,000.

Divide 44,850 by 5.

With either method, we see that there was an amazing 8,970% increase in the value

of the Kennedy rocking chair.

8,970x

44,850

5

x

44,850,000

5,000

x

44,850,000

5,000



5,000

1

x

5,000

1

8970

5  44,850

 40

48

 45

35

 35

0

 0

0

Caution! The percent of increase (or decrease) is a percent of the original

number,that is, the number before the change occurred. Thus, in Example 6, it

would be incorrect to write a percent sentence that compares the increase to

the new valueof the Kennedy rocking chair.

$448,500 is what percent of $453,500?

Finding the Percent of Increase or Decrease

To find the percent of increase or decrease:

1. Subtract the smaller number from the larger to find the amount of
   increase or decrease.


2. Find what percent the amount of increase or decrease is of the original
   amount.

EXAMPLE (^7) Commercials Jared Fogle credits
his tremendous weight loss to exercise and a diet of low-fat
Subway sandwiches. His maximum weight (reached in
March of 1998) was 425 pounds. His current weight is about
187 pounds. Find the percent of decrease in his weight.
StrategyWe will begin by finding the amount of decrease
in Jared Fogle’s weight.
WHYThen we can calculate what percent of his original
425-pound weight that the decrease represents.
SolutionFirst, we find the amount of decrease in his weight.
Subtract his new weight fromhis weight before
going on the weight-loss program.
His weight decreased by 238 pounds.
Next, we find what percent of his original 425 weight the 238-pound decrease
represents by translating the problem into a percent equation (or percent
proportion) and solving it.

425  187  238

Self Check 7

REDUCING FAT INTAKEOne serving

of the original Jifpeanut butter

has 16 grams of fat per serving.

The new Jif Reduced Fatproduct

contains 12 grams of fat per

serving. What is the percent

decrease in the number of grams

of fat per serving?

Now TryProblem 37

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