Final ExamMath Review

  1. In 1988, the N.Y. Mets won the pennant in the National League East with a record of 100 wins and 60 losses. What percent of their games did the Mets win? Show your work.

62.5% =100 ÷ (100+60)

  1. This circle graph shows the methods of transportation used by students at Sunny Shores School.

a. What percent of students come by car?

30% (=100% – 14% – 20% – 36%)

b. Express the part for students using car and bicycle as transportation as a fraction.

Car 3/10

Bicycle 7/50

c. How many students choose to walk to school if there are 250 students in the school?

250 ×20% = 50

You know the total (250) and the % of a part, you times the total by the % to find the part.

  1. The Recommended Daily Allowance (RDA) of calcium for teenagers is 1200 milligrams. One day, Tina consumed 1500 milligrams of calcium. What percent of the RDA did Tina consume?

125% (what percent × 1200 = 1500; 1200 is the base)

  1. 225% of what number is 81?

36 (= 81/225% or Number × 225% = 81)

  1. The 15% tip on Craig’s lunch bill came to $2.40. What was the amount of the bill before the tip?

$16 (=$2.4/15% or Bill × 15% = Tip)

You know the part and its corresponding %, you divide the part by the % to find the total or base.

  1. Jared has priced a laptop computer at two stores. At Royal Electronics, the computer sells for $1,150, and there is a 15% off sale this month. At Crown Computers, the same laptop sells for $1,240, and there is a 20% off sale this month. Where will the computer cost less? How much will it cost?

Royal Electronics=$1150 × (1–15%) = $977.5, Crown Computer=$1240 × (1–20%) = $992. Royal Electronics costs less ($992–$977.5=$14.5)

  1. An ad shows a box of detergent (2 lb.) selling for $10 while a smaller box with half as much (1 lb.) detergent selling for half as much ($5). Would you consider this a bargain?

No

Ratio of price to pound (unit price) is the same for both boxes.

  1. Your local supermarkets sell peaches at different prices for different amount. Which is the best deal?
  1. $1.29/lb.
  2. $2.50 for 2 lb.
  3. 10 lb. for $8.
  4. Buy 2 lb. for $3 and Get one lb. free.

Unit price for all choices: a. $1.29/lb.; b. $1.25/lb.; c. $8/10 = $0.8/lb.; d. $3/(2lb. + 1 lb.) = $1/lb.

  1. It took John 30 minutes to roll 100 of his 1,000 newspapers. At this rate, how long would it take him to roll all of them?
  1. 5 hours
  2. 30 hours
  3. 100 minutes
  4. 3,000 minutes.

(30/100) ×1000 = 300 minutes = 5 hours

Percent increase and decrease of a value measure how that value changes, as a percentage of its original value(base).

  1. A collectors' comic book is worth $120 in 1994, and in 1995 its value is $132. What is the percent increase of the book?

The change is $132 - $120 = $12, an increase in price of $12; since $12/$120 = 10%, we say its value increased by 10% from 1994 to 1995.

  1. The numbers of scooters sold by a manufacturer are shown in the table.

Monthly Scooter Sales

September / 4,000
October / 4,400
November / 4,840
December / ?

a. Explain the pattern.

Each year the number of scooters increases by 10%.

(4400 – 4000) / 4000 = 0.1 = 10%

(4840 – 4400) / 4400 = 0.1 = 10%

b. Assuming the pattern continues, find the sales for December.

5324 (=4840 + 4840 × 10% = 4840 × 110%)

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