Novotny Solving Percent Problems

Percent Change

100

Percent increase from 5 to 8.

60%

200

Percent decrease from 5 to 1.

80%

300

Percent decrease from 20 to 15.

25%

400

Percent increase from 20 to 30.

50%

500

Percent decrease from 55 to 44.

20%

Tax

100

Cost: $10

Tax: 20%

How much tax will be added?

$2

200

Cost: $20

Tax: 15%

How much tax will be added?

$3

300

Daily Double! 

Cost: $56

Tax: $3.92

What is the tax rate? 

7%

400

Cost: $110

Tax: 23%

What will the total cost be?

$135.30

500

Cost: $310

Tax: 7.2%

What will the total cost be?

$332.32

Percent Error

100

Estimated amount: $6

Actual amount: $10

What is the percent error?

40%

200

Estimated amount: 2 feet

Actual amount: 8 feet

What is the percent error?

75%

300

Estimated amount: 43 people

Actual amount: 50 people

What is the percent error?

14%

400

Estimated amount: 100

Actual amount: 85

What is the percent error?

18% or 17.6%

500

Estimated amount: $60

Actual amount: $58.12

What is the percent error?

3% or 3.2%

Discounts

100

Price: $20

Discount: 30%

What is the sale price?

$14

200

Price: $40

Discount: 15%

What is the sale price?

$34

300

Price: $130

Discount: 23%

What is the sale price?

$100.10

400

Price: $250

Discount: 33%

What is the sale price?

$167.50

500

Price: $1745

Discount: 12%

What is the sale price?

$1,535.60

Interest

100

Principal: $100

Rate: 5%

Years: 1

How much interest will be earned?

$5

200

Principal: $500

Rate: 8%

Years: 1

How much interest will be earned?

$40

300

Principal: $3500

Rate: 8.2%

Years: 1

What will the account balance be?

$3,787.00

400

Principal: $7000

Rate: 4.3%

Years: 1

What will the account balance be?

$7,301.00

500

Daily Double - Ace's father "borrowed" $80 from him on Monday.  Ace told him he will be charging him interest EACH day.  On Tuesday he told his father he owed him $81.60.  What is the interest rate that Ace is charging his father?   

2%