Section 2.7 Basic Percent Applications

Solve each of the following applications using and showing the 4 step method presented in class.

1. Jerry made an investment of $55,000 last year in some stocks and lost 12% of what he invested. How much did he lose?

If he sold the stock at the end of the year, what was the selling

price?

2. With a discount of 70%, the price of a bracelet is $17.99. What was the price before the discount? (Round to the nearest cent)

3. Mike bought a bicycle and then sold it for 20% more than he paid for it. If he sold the bike for $144, what did he pay for it?

4. The number of employees at Arnold’s Box Manufacturers just decreased from 210 to 180. Find the percent decrease. Round to the nearest tenth of a percent.

5. Sue made an investment of $48,000 in some stocks last year. The stocks were worth $51,840 at the end of the year. What was the percent increase in her stocks?

Answers:

1. Jerry lost $6600. The selling price was $48,400. 2. The price without the discount is $59.97.

3. Mike paid $120 for the bike. 4. It was a 14.3% decrease. 5. It was an 8% increase.

Section 2.7 More Applications

1. A 12% acid solution is to be mixed with a 20% acid solution to obtain 10 gallons of 14% acid solution. How many gallons of each solution should be used in the mix?

2. How much water should be added to 30 gallons of a solution that is 70% antifreeze in order to get a mixture that is 60% antifreeze?

3. Which of the following mixtures cannot be obtained by mixing a 15% salt solution with a 25% salt solution? a) 10% b) 18% c) 22% d) 30% (Reasoning question)

4. A grocer has 60 pounds of candy worth $2 per pound. She wants to upgrade this to candy worth $3.25 per pound by mixing it with candy worth $4.50 per pound. How many pounds of the $4.50 candy should she use?

5. Karen invested some money at 9% annual simple interest and $250 more than that at 10% annual simple interest. If her total yearly interest was $101, how much was invested at each rate?

6. Kim won $60,000 on a slot machine in Las Vegas. She invested part at 8% simple interest and the rest at 12%. She earned a total of $6200 in interest. How much was invested at each rate?

7. How long will it take a bus traveling at 60 miles per hour to overtake a car traveling at 40 mph if the car had 1.5-hour head start? How far from the starting point are they?

8. On the first half of a trip Gary traveled at an average speed of 70 mph. He then stopped for a half-hour break. He continued on the second half of his trip at 55 mph. If the entire trip took 6.5 hours including the stop of ½ hour, how much time did the first half of Gary’s trip take? How far did Gary travel on his entire trip?

9. Dave and his brother Andy leave their home driving in opposite directions during rush hour traffic. Dave averages 45 mph and Andy averages 35 mph. How long can they talk on their direct-connect walkie-talkie phones until they are out of its 60-mile range?

Answers: 1. They should use 7.5 gallons of 12% and 2.5 gallons of 20% in the mix. 2. Five gallons of water should be added. 3. Both 10% and 30% cannot be obtained. The concentration of the mix cannot be less than the lowest concentration (15%) or more than the highest concentration (25%).

4. The grocer needs to use 60 pounds of the $4.50 candy. 5. Karen invested $400 @ 9% and $650 at 10%. 6. Kim invested $25,000 at 8% and $35,000 at 12%. 7. It will take 3 hours. They will be 180 miles from the starting point. 8. It will take 2.64 hours. The total distance is 369.6 miles.

9. The can talk for ¾ of an hour (or 45 minutes).