(X-2)/13=n, where n is a non-negative integer

[wawan_andrean]

(X-2)/13=n, where n is a non-negative integer, and X is a positive integer less than 100. Basically determine how big the subset for possible values of n, and you have your answer.

I'm wondering how come the answer is 8. My opinion is 7

13n=X-2
X=13n+2, since X is positive integer less than 100, hence the value of n based on above condition is 7 (X=93).

The answer 8 is because they consider 0 (zero) as well, if apply in the aquation all integer less than 100 having reminder 2 if divided by 13 are the following:

2, 15, 28, 41, 54, 67, 80, 93

IMO, 2 is not satisfied with the condition.

Need help to deal with this to get better approach/understanding.

Thx

[jnelson0612]

Yes, 2 does work as a value for X. Let's evaluate again:

The problem says that
n is a non-negative integer (so any positive integer or zero)
X is a positive integer less than 100

The equation says:
13n=X-2
X is a positive integer less than 100; X could be 2.
n is a non-negative integer; n could be 0.

Thus, 2 does work a value for X. Please let us know if you need further clarification.