C3a
Practice - Percentages
TRY TO ANSWER IN TWO AND A HALF MINUTES.
QUESTIONS
QUESTIONS
1. What is 0.567 expressed as a percentage? What is it rounded to the nearest whole percent?
2. What is 1/2 of 24 percent?
3. What is 35% of 165%?
4. In a cooking competition, 75% of the points are awarded for taste and 25% are awarded for presentation. You score 84 points for taste and 68 points for presentation. What is your overall score?
5. You have a bicycle which costs $100. You decide to mark up the price by 60%. a) What is your selling price? The bicycle doesn't sell, so you decide to mark down the selling price by 60%. b) What is the new selling price? Does this price cover your cost?
6. Twenty percent of the workers in your sandwich shop are paid at the minimum wage. If 16 workers are paid at the minimum wage, how many workers are there?
7. You buy a motorcycle for $2400. The down payment is $480. What percent is the down payment?
8. Your employer gives you a 23% commission on everything you sell. In one month you sold merchandise worth $3400. How much was your commission?
9. Three tablespoons of peanut butter contains 4 grams of saturated fat and 11 grams of unsaturated fat. This amount of fat is 20% of the daily recommended amount of fat in a 2000 calorie diet. How many grams of fat are recommended daily?
10. A stadium seats 17,250 people. For an event, 88% of the tickets are sold. How many seats are sold?
11. In 2011, a person received $52,500 in salary and $6,250 in bonuses. In 2012, the person received $56,300 in salary and $4,100 in bonuses. What was the person's percentage increase or decrease in total compensation?
ANSWERS
1. It is 56.7%. Rounded, it is 57%.
2. Change the 1/2 to 0.5 and the 24% to 0.24, then multiply to get 0.12, or 12%. Or divide 24% by 2. With the built-in calculator, you could enter both numbers directly without conversions.
3. Change 35% to 0.35 and change 165% to 1.65, then multiply to get 0.5775. With the built-in calculator, you could enter both numbers directly without conversions.
4. For taste, you get 84 times 75%, or 84 x .75 = 63 points. For presentation, you get 68 times 25%, or 68 x .25 = 17 points. Your total score is 63 + 17 = 80 points. You can do all of this in one step with the built-in calculator.
5. a) The first markup is $100 x 60%, or $60. So the first selling price is $100 + $60 = $160. b) The markdown is $160 x 60%, or $96. So the marked-down selling price is $160 - $96, or $54. You do not cover your original $60 cost at the second selling price.
6. Set up the equation .2x = 16. So x = 16/.2 = 80.
7. $480/$2400 = .20, or 20 percent.
8. $3400 x 23% = $3400 x .23 = $782.
9. 15 grams / 20% = 15/.2 = 75 grams daily.
10. 17,250 x 88% = 17,250 x .88 = 15,180 seats.
11. First you have to add salary and bonuses to get total compensation for year year. In 2011 that was $52,500 + $6,250 = $58,750. In 2012 it was $56,300 + $4,100 = $60,400. Since the 2012 total is greater than the 2011 total, there was an increase. The percentage increase is the difference ($60,400 - $58,750 = $1650) divided by the 2011 figure ($58,750), which is 0.28 in decimal form, which is 2.8%.
CALCULATOR STEPS
In addition to the calculator keys used in the preceding pages, the "2nd" and " ( " keys are used together here to produce %.
1. The calculator will not do this problem directly.
2. Press on and clear. Key in 24. Press 2nd and ( . Press x . Press n/d. Key in 1. Press down. Key in 2. Press enter. The screen should show ".12".
3. Press on and clear. Key in 165. Press 2nd and ( . Press x . Key in 35. Press 2nd and ( . Press enter. The screen should read "0.5775".
4. Press on and clear. Press ( . Key in 84. Press x . Key in 75. Press 2nd and ( . Press ) . Press + . Press ( . Key in 68. Press x . Key in 25. Press 2nd and ( . Press ). Press enter. The screen should show "80".
5. a) Press on and clear. Key in 100. Press + . Press ( . Key in 100. Press x . Key in 60. Press 2nd and ( . Press ) . Press enter. The screen should show "160". b) Press clear. Key in 160. Press - . Press ( . Key in 160. Press x . Key in 60. Press 2nd and ( . Press ) . Press enter. The screen should show "64".
6. Press on and clear. Key in 16. Press ÷ . Key in 20. Press 2nd and ( . Press enter. The screen should show "80".
7. Press on and clear. Key in 480. Press ÷ . Press 2400. Press enter. The screen should show "0.2".
8. Press on and clear. Key in 3400. Press x . Key in 23. Press 2nd and ( . Press enter. The screen should show "782".
9. Press on and clear. Key in 15. Press ÷. Key in 2. Press 2nd and ( . Press enter. The screen should show "75".
10. Press on and clear. Key in 17.250. Press x . Key in 88. Press 2nd and ( . Press enter. The screen should show "15.18".
11. Do this in three steps. a) Press on and clear. Key in 17250. Press + . Key in 6250. Press enter. The screen should show "58750". b) Press clear. Key in 56300. Press + . Key in 4100. Press enter. The screen should show "60400". c) Press clear. Press ( . Key in 60400. Press - . Key in 58750. Press ) . Press ÷. Key in 58750. Press enter. The screen should show "0.28...".