what is a common denominator

ATI TEAS 7

Practice Math TEAS TEST

1. What is a common denominator?

A. A shared multiple of two denominators
B. A shared factor of two numerators
C. A number that is the same in all fractions
D. A number that divides evenly into both fractions

Correct answer: A

Rationale: A common denominator is a shared multiple of the denominators in a set of fractions. It is necessary when adding or subtracting fractions to have a common denominator to ensure that the fractions can be combined accurately. Choice B is incorrect because the common denominator is related to the denominators, not the numerators. Choice C is incorrect because while the common denominator is the same in all fractions being added or subtracted, it is not necessarily a number that is the same in all fractions. Choice D is incorrect because a common denominator is a multiple of the denominators, not a number that divides evenly into both fractions.

2. The cost, in dollars, of shipping x computers to California for sale is 3000 + 100x. The amount received when selling these computers is 400x dollars. What is the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost?

A. 10
B. 15
C. 20
D. 25

Correct answer: B

Rationale: To find the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost, we set up the inequality 400x >= 3000 + 100x. Simplifying this inequality gives 300x >= 3000, and dividing by 300 results in x >= 10. Therefore, at least 15 computers must be shipped and sold to cover the shipping cost, making choice B the correct answer. Choices A, C, and D are incorrect as they represent numbers less than 15, which would not cover the shipping cost.

3. Four friends are sharing a pizza. One friend eats half of the pizza. The other three friends equally divide the rest among themselves. What portion of the pizza did each of the other three friends receive?

A. 1/5
B. 1/3
C. 1/4
D. 1/6

Correct answer: D

Rationale: After one friend eats half of the pizza, there is half left. This remaining half is divided equally among three friends. To find the portion each of the other three friends receives, we divide 1/2 by 3, which equals 1/6. Therefore, each of the other three friends receives 1/6 of the pizza. Choice A, 1/5, is incorrect because the correct portion is 1/6. Choice B, 1/3, is incorrect as each of the three friends receives 1/6. Choice C, 1/4, is incorrect as well since the correct portion is 1/6.

4. Simplify the following expression: 3 (1/6) - 1 (5/6)

A. 2 (1/3)
B. 1 (1/3)
C. 2 (1/9)
D. 5/6

Correct answer: B

Rationale: To simplify: First, subtract the whole numbers: 3 - 1 = 2. Then, subtract the fractions: (1/6) - (5/6) = - (4/6) = - (2/3). Now, subtract (2 - 2/3) = 1 (1/3).

5. Which of the following is the decimal form of 87.5%?

A. 875
B. 8,750
C. 0.875
D. 8.75

Correct answer: C

Rationale: To convert a percentage to a decimal, you move the decimal point two places to the left. Therefore, 87.5% as a decimal is 0.875. Choice A (875) is incorrect as it represents the percentage without converting to a decimal. Choice B (8,750) is incorrect as it represents the percentage in whole numbers without decimal conversion. Choice D (8.75) is incorrect as it represents 875% instead of 87.5%.