Answer Keys: Percent Applications

Student Concept Worksheet Answers

1

Tax: $3.00 | Total: $53.00

Tax = 0.06 x $50 = $3.00. Total = $50 + $3 = $53.00

2

Discount: $45 | Sale Price: $105

Discount = 0.30 x $150 = $45. Sale price = $150 - $45 = $105. Or: 0.70 x $150 = $105

3

Change: 1,500 | Percent increase: 30%

Change = 6,500 - 5,000 = 1,500. Percent = 1,500/5,000 x 100 = 30%

4

I = 800 x 0.03 x 5 = $120

P = $800, r = 3% = 0.03, t = 5. I = 800 x 0.03 x 5 = $120

Practice Worksheet Answers

Part A: Tax and Tip

#	Answer	Explanation
1	Tax: $1.96	0.07 x $28 = $1.96
2	Tip: $9.00	0.20 x $45 = $9.00
3	Total: $38.72	Tax: 0.06 x 32 = $1.92; Tip: 0.15 x 32 = $4.80; Total: $32 + $1.92 + $4.80 = $38.72
4	Original: $50	$54 = 1.08x; x = 54/1.08 = $50

Part B: Discount and Sale Price

#	Answer	Explanation
5	$45	Discount = 0.25 x 60 = $15; Sale = $60 - $15 = $45 (or 0.75 x 60)
6	$48	0.40 x $120 = $48
7	15%	Discount = $120; 120/800 = 0.15 = 15%
8	$80	$56 = 0.70x; x = 56/0.70 = $80

Part C: Percent Increase and Decrease

#	Answer	Explanation
9	30%	(52-40)/40 x 100 = 12/40 x 100 = 30%
10	20%	(45-36)/45 x 100 = 9/45 x 100 = 20%
11	20%	(25000-20000)/25000 x 100 = 5000/25000 x 100 = 20%
12	30%	(15600-12000)/12000 x 100 = 3600/12000 x 100 = 30%

Part D: Simple Interest

#	Answer	Explanation
13	I = $120; Total = $1,120	I = 1000 x 0.04 x 3 = $120; Total = $1000 + $120
14	$250	I = 2500 x 0.025 x 4 = $250
15	$60	I = 500 x 0.06 x 2 = $60
16	$525	I = 3000 x 0.035 x 5 = $525

Part E: Word Problems

17

25%

(240-180)/240 x 100 = 60/240 x 100 = 25% decrease

18

$40

Markup = 0.60 x $25 = $15; Retail = $25 + $15 = $40

19

$1,740

I = 1500 x 0.08 x 2 = $240; Total = $1500 + $240 = $1,740

20

$93.75

Tax = 0.07 x 75 = $5.25; Tip = 0.18 x 75 = $13.50; Total = $75 + $5.25 + $13.50 = $93.75

Challenge Questions:

#21: NO, they are NOT the same! 20% off $100 = $80. Then 10% off $80 = $8 off, so $72 final. But 30% off $100 = $70. The stacked discounts give $72, not $70. Stacked discounts always give less savings!

#22: NO, the final price is NOT equal to the original! Start: $80. After 25% increase: $80 x 1.25 = $100. After 25% decrease: $100 x 0.75 = $75. Final price is $75, not $80! The percent decrease is calculated on the larger amount.

FAST Practice Quiz Answers

1

C) $30

25% of $40 = 0.25 x 40 = $10 discount. Sale price = $40 - $10 = $30. (Or: 75% x $40 = $30)

2

B) 25%

Change = 1000 - 800 = 200. Percent = 200/800 x 100 = 25%. Note: A (20%) would be if dividing by new (200/1000), which is wrong.

3

B) $90

I = P x r x t = 600 x 0.05 x 3 = $90. Note: C ($630) and D ($690) include principal, but question asks for INTEREST only.

4

Select: 6% tax = $3.00, 15% tip = $7.50, 20% tip = $10.00

6% tax = $3.00 (0.06 x 50 = 3) CORRECT
15% tip = $7.00 INCORRECT (should be $7.50)
15% tip = $7.50 (0.15 x 50 = 7.50) CORRECT
20% tip = $10.00 (0.20 x 50 = 10) CORRECT
8% tax = $4.50 INCORRECT (should be $4.00)

5

A) 25%

Change = 1200 - 900 = 300. Percent = 300/1200 x 100 = 25%. Divide by ORIGINAL ($1200).

6

D) $2,240

I = 2000 x 0.06 x 2 = $240. Total = $2000 + $240 = $2,240. A and B are just the interest; C forgot one year.

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