Question 752588: when 200 is divided by a positive integer N, the remainder is 5. the number of all possible values of N is:
A) 2
B)6
C)8
D)13
E)16
Thank you very much for looking at this question. I have worked out that N - 40, but I'm not sure how to continue on from there.
Answer by Edwin McCravy(20056) (Show Source):
You can put this solution on YOUR website!
Suppose we divided N into 200 and got quotient Q and remainder 5,
like this:
Q
N)200
N·Q
5
Then to check that division by multiplying, we'd have
200 = N·Q + 5
or
195 = N·Q
So we just write down all the possibilities for N and Q,
which amounts to writing down all the ways to write 195
as a product of two positive integers:
195 = N·Q
-------------
195 = 1·195
195 = 3·65
195 = 5·39
195 = 13·15
195 = 15·13
195 = 39·5
195 = 65·3
195 = 195·1
And of course. each of those 8 cases of N gives remainder 5
when we divide 200 by N:
195 65 39 15
1)200 3)200 5)200 13)200
195 195 195 195
5 5 5 5
13 5 3 1
15)200 39)200 65)200 195)200
195 195 195 195
5 5 5 5
Answer: 8
Edwin
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