Question

When the positive integer n is divided by 45, the remainder is 18. Which of the following must be a divisor of n ?
A. 11 B. 9 C. 7 D. 6 E. 4

Answer 1

Answer:

9

Step-by-step explanation:

The question tells you that n can be expressed in the form of

n = 45k + 18

When the positive integer n is divided by 45, the remainder is 18

Therefore, to find the answer:

Out of the given options, which one must be a divisor of n

Approach and Working:

When n is divided by 45, let’s assume that the quotient is k, with the remainder 18

Therefore, we can write n = 45k + 18

this explains why the question can be expressed this way

Next, irrespective of the value of k, n will be divisible by a number if 45 and 18 both are divisible by that number

From the given options, only 9 can divide both 45 and 18

Hence, the correct answer is option B.