Problem Solving

jenlee wrote:When positive integer A is divided by positive integer B, the result is 4.35. Which of the following could be the remainder when A is divided by B?

A/B = 4.35 ---> A = (4.35)*B = 4B + (0.35)*B

Hence, when A is divided by B, the remainder is (0.35)*B = 35B/100 = 7B/20 = 7*(B/20)

Hence, the remainder must be a multiple of 7.

The correct answer is B.

jenlee wrote:When positive integer A is divided by positive integer B, the result is 4.35. Which of the following could be the remainder when A is divided by B?

(A) 13
(B) 14
(C) 15
(D) 16
(E) 17

Another approach:

We're told that A/B = 4.35
In other words, A/B = 435/100
Simplify: A/B = 87/20
87 divided by 20 gives us a remainder of 7. Check the answer choices: 7 is not an option.

Aside: At this point, we may might recognize that if we double 87 and 40, the remainder will also be doubled, to get [spoiler]14 = B[/spoiler] Or, we can continue with our other line of thought . . .

Since 87 divided by 20 didn't yield a remainder found in the answer choices, let's try a fraction that's equivalent to 87/20
How about 174/40?
174 divided by 40 gives us a remainder of 14. Check the answer choices: 14 is an option.
Answer: B

Cheers,
Brent