gettinit wrote:

when 777 is divided by positive integer n, the remainder is 77. How many possibilities are there for n?

a. 2

b. 3

c. 4

d. 5

e. 6

Let me your thought process on this. I know we have to put this in remainder format of n(y) + 77= 777 so n(y)=700 but from here I would find the number of factors for 700 to be 18. Is there a quicker way of figuring out the number of factors greater than 77?

Positive integer

a divided by positive integer

d yields a reminder of

r can always be expressed as

a=qd+r, where

q is called a quotient and

r is called a remainder, note here that

0\leq{r}<d (remainder is non-negative integer and always less than divisor).

So we'd have:

777=qn+77, where

remainder=77<n=divisor -->

qn=700=2^2*5^2*7 --> as

n must be more than 77 then

n could take only 5 values: 100, 140, 175, 350, and 700 (the least factor more than 77 is

2^2*5^2=100, now if you

substitute 2, 2^2, and 5 by 7 you'll get the factors more than 100 plus if you

include 7 you'll get one more factor, 700 itself, so total 1+3+1=5).

Answer: D.

Discussed here:

remainder-101074.html?hilit=possibilities#p782422Hope it's clear.

THanks for the reference Bunuel. So I am guessing its best to write out the factors in these types of questions? I didn't quite understand your methodology of replacing 2, 2^2, and 5 by 7 etc. I understand how it is applied here but if this were a different question I'd be lost. I think the key is just to mulitply the different factors to arrive at numbers larger than 77.