which of the following is not a way to write 40 percent of n

ATI TEAS 7

TEAS Math Practice Test

1. Which of the following is NOT a way to write 40 percent of N?

A. 0.4N
B. N/40
C. 2/5 N
D. 40N/100

Correct answer: B

Rationale: The correct answer is B: N/40. To find 40% of N, you multiply N by 0.4, so 0.4N is the correct representation. Choice B, N/40, is incorrect because dividing N by 40 does not give you 40% of N. Choice C, 2/5 N, is equivalent to 40% of N since 2/5 is the same as 40% when simplified. Choice D, 40N/100, is also correct since 40% can be represented as 40/100, which simplifies to 0.4, making 40N/100 another valid way to write 40% of N.

2. A scientist is trying to determine how much poison will kill a rat the fastest. Which of the following statements is an example of an appropriate hypothesis?

A. Rats that are given lots of poison seem to die quickly.
B. Does the amount of poison affect how quickly the rat dies?
C. The more poison a rat is given, the quicker it will die.
D. Poison is fatal to rats.

Correct answer: C

Rationale: A valid hypothesis must be a testable statement that predicts a relationship between variables. Option C is the only statement that presents a clear cause-and-effect relationship between the amount of poison given and the time it takes for the rat to die. Option A is descriptive without predicting an outcome, option B is a question rather than a statement, and option D is a general fact about poison and rats, lacking a specific hypothesis for testing.

3. What defines a composite number?

A. A number with only two factors
B. A number that is a fraction
C. A number with more than 2 factors
D. A number with exactly two factors

Correct answer: C

Rationale: A composite number is a positive integer greater than one that has more than two factors. Choice A is incorrect because a number with only two factors is a prime number. Choice B is incorrect as being a fraction does not define a composite number. Choice D is incorrect because a number with exactly two factors is a prime number, not a composite number.

4. What is the difference between two negative numbers?

A. Negative number
B. Positive number
C. Zero
D. Not enough information

Correct answer: B

Rationale: The correct answer is B: 'Positive number.' When you subtract one negative number from another negative number, the result can be a positive number. For example, the difference between -5 and -3 is 2, which is a positive number. Choice A, 'Negative number,' is incorrect because the result of subtracting two negative numbers can be positive. Choice C, 'Zero,' is incorrect because the difference between two negative numbers is not always zero. Choice D, 'Not enough information,' is incorrect because there is enough information to determine that the difference between two negative numbers can be a positive number.