SECTION 2.7 Further Applications of Linear Equations^139
Convert each decimal to a percent. See Examples 7(c) and 7(d).
83.0.80 84.0.75 85.0.02 86.0.06
87.0.125 88.0.983 89.2.2 90.1.4Solve each problem. See Examples 8 and 9.
91.What is 14% of 780? 92.What is 26% of 480?
93.42% of what number is 294? 94.18% of what number is 108?
95.120% of what number is 510? 96.140% of what number is 315?
97.4 is what percent of 50? 98.8 is what percent of 64?
99.What percent of 30 is 36? 100.What percent of 48 is 96?
101.Find the discount on a leather recliner with a regular price of $795 if the recliner is 15%
off. What is the sale price of the recliner?
102.A laptop computer with a regular price of $597 is on sale at 20% off. Find the amount
of the discount and the sale price of the computer.
103.Clayton earned 48 points on a 60-point geometry project. What percent of the total
points did he earn?
104.On a 75-point algebra test, Grady scored 63 points. What percent of the total points did
he score?
105.Anna saved $1950, which was 65% of the amount she needed for a used car. What was
the total amount she needed for the car?
106.Bryn had $525, which was 70% of the total amount she needed for a deposit on an
apartment. What was the total deposit she needed?OBJECTIVES OBJECTIVE 1 Use percent in solving problems involving rates.Recall
from Section 2.6that the word “percent” means “per 100.”
1%0.01, or 1%
1
100
Further Applications of Linear Equations
2.7
1 Use percent in
solving problems
involving rates.
2 Solve problems
involving mixtures.
3 Solve problems
involving simple
interest.
4 Solve problems
involving
denominations
of money.
5 Solve problems
involving distance,
rate, and time.
Mixing different concentrations of a substance or different interest rates involves
percents. To get the amount of pure substance or the interest, we multiply.
In an equation, percent is always written as a decimal or a fraction.
PROBLEM-SOLVING HINT
Mixture Problems Interest Problems (annual)
base rate (%) percentage principal rate (%) interest
b : r p p : r I
: :
Solve each equation. See Section 2.3.
- 109.0.92x+0.98 112 - x 2 =0.96 1122 110.0.10 172 +1.00x=0.30 17 +x 2
0.15x+0.30 132 =0.20 13 +x 2 0.20 1602 +0.05x=0.10 160 +x 2