Questions & Answers (Rated A+)
Dana receives $30 for her birthday and $15 for cleaning the garage. If she spends $16 on a CD, how much money does she have left? - ANSWER - A. $29
B. $27
C. $24
D. $12
(A) Add the amount of money received and subtract the amount spent. $30 + $15 - $16 = $29.
In a manufacturing plant that produces new computers, a 0.15 probability exists that a computer will be defective. If five computers are manufactured, what's the probability that all of them will be defective? - ANSWER - A. 7.6
B. 0.60
C. 0.000076
D. 0.00042
(C) The probability that all five computers will be defective is 0.15 × 0.15 × 0.15 × 0.15 ×
0.15 = 0.0000759 (round up to 0.000076).
A house contains one 12-foot-×-14-foot bedroom, one 12-foot-×-10-foot bedroom, and one 8-foot-×-12-foot bedroom. What's the total amount of carpeting needed to carpet all three bedrooms? - ANSWER - A. 384 square yards
B. 42 2/3 square yards
C. 216 square yards
D. 88 square yards
(B) Find the area of each bedroom and add them together: 12 × 14 = 168; 12 × 10 = 120; 8 × 12 = 96. 168 + 120 + 96 = 384 square feet. Then, because 9 square feet make up a square yard, divide the total area in square feet by 9 to determine the number of square yards needed: 384 ÷ 9 = 42 2/3 square yards.
If 4 people can run 8 machines, how many machines can 2 people run? - ANSWER - A.
2
B. 1
C. 4
D. 3
(C) Two people is 1⁄2 as many as 4 people: 2 ÷ 4 = 1⁄2. Multiply the number of machines 4 people can run by 1⁄2 to determine how many machines 2 people can run: 8
× 1⁄2 = 4. The product of two consecutive odd numbers is 399. What are the numbers? - ANSWER - A. 17 and 19
B. 19 and 21
C. 21 and 23
D. 25 and 27
The fastest way to solve this would be to simply multiply the possible choices together (19 × 21 = 399). You can also solve this with algebra. Let x equal the first number and x + 2 the second number.
x(x + 2) = 399
x^2 + 2x = 399 (Note: This is a quadratic equation that can be solved by setting it equal to zero and factoring.)
x^2 + 2x - 399 = 0
(x - 19)(x + 21) = 0
x - 19 = 0 x + 21 = 0
x = 19 x = -21
x + 2 = 21 x + 2 = -19
(B) Two solutions are possible: 19 and 21, and -21 and -19. Because the latter pair isn't one of the answer choices, the first pair is the correct answer.
A bricklayer charges $8 per square foot to lay a patio. How much would it cost for the bricklayer to lay a 12-foot-×-16-foot patio? - ANSWER - A. $960
B. $192
C. $224
D. $1536
(D) First determine the square footage of the patio: 12 feet × 16 feet = 192 square feet. Then multiply this number by the cost per square foot to determine what the brick layer charges: 192 × $8 = $1,536
Your piggy bank contains $19.75 in dimes and quarters. There are 100 coins in all. How
many dimes are there? - ANSWER - A. 25
B. 30
C. 35
D. 40
(C) Let x equal the number of dimes. Then 100 - x represents the number of quarters. There is $0.10x in dimes and $0.25(100 - x) in quarters.
0.10x + 0.25(100 - x) = 19.75
0.10x + 25 - 0.25x = 19.75