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Question 19

This question is dependent on the understanding of the vocabulary in the question. The key vocabulary is:

Integer = positive and negative whole numbers plus the number 0. Examples: -3, -2, -1, 0, 1, 2, 3

Divisor = number 1 is a divisor of number 2 if number 1 divides into number 2 without a remainder.
Examples: 5 is a divisor of 30, 4 is a divisor of 16

Prime = a number with exactly two different positive divisors 1 and itself. Examples: 2, 3, 5, 7, 11

The issue is whether one can determine if r is a prime number.

Statement (1) by itself: We know that 5 is a positive integer and that each of 5 and t is positive.

The relationship 5r = t be will satisfied whether r is or is not prime.

Test it this way.

3 is a prime number. 5 times 3 = 15.

6 is not a prime number. 5 times 6 = 30.

Since both 15 and 30 are positive integers, statement (1) does not allow one to determine whether r is a prime.

This rules out choices (A) and (D).

Statement (2) by itself: Remember that r divides evenly into t and that r and t are positive integers.

The smallest integer that is greater than 1 is 2. It is possible for t to be an even integer. If t is an even integer then 2 is the smallest divisor of t. Since 2 is a prime number the question can be answered from statement (2) alone.

Hence, the answer is (B).

Back to the tutorial. Go to question 20.

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