SECTION 4.6 APPLICATIONS OF PERCENT

Percent * Base = Percentage (or amount)

Examples: Exercises from pages 243-244

2. What number is 7% of 300?

Let N = the number

N = 0.07(300)

N = 21

Twenty-one is 7% of 300.

4. 450 is 110% of what number?

Let N = the number

450 = 1.10N

409.09 = N

450 is 110% of 409.09.

10. 12.5% of what number is 40?

Let N = the number

0.125N = 40

N = 320

Twelve and a half percent of 320 is 40.

18. 30 is what percent of 150?

Let p = the percent (in decimal form)

30 = 150p

0.2 = p

Thirty is 20% of 150.

24. If a student answered 72 out of 96 questions correctly, what percent did the student answer correctly?

Let p = the percent (in decimal form)

p(96) = 72

p = 0.75

The student answered 75% of the questions correctly.

34. A union contract calls for a 6% increase in the hourly rate of pay. If the current rate is $7.50, what is the increase in the hourly wage?

Let I = the increase

0.06(7.50) = I

0.45 = I

The hourly wage increased $0.45.

40. A used car is on sale for $1000. It was originally priced $1500. What is the percent of the decrease in the cost?

Let P = the percent in decimal form

The amount of the decrease is $1500 - $1000 = $500.

P(1500) = 500 Percent(original price) = discount

P = 0.3333

The car decreased in price by 33.3%

44. A cook’s salary is $1200 per month. From this amount the cook pays $468 for social security and other taxes. What percent of the salary goes for taxes?

P = percent in decimal form

1200p = 468

p = 0.39

The cook pays 39% of his salary in taxes.