<p>I've seen problems like this in the past, but I just can't remember how to do it. I know it's really simple once you see the concept.
If the length of LM is 7 and the length of MN is 8,
which of the following could be the length of LN ?
(A) 23
(B) 22
(C) 17
(D) 16
(E) 14
</p>
<p>(E), the longest side of the triangle must be less than the sum of the other two sides.
E is the only choice below 15</p>
<p>the 3rd side’s length cannot exceed the sum of the 2 sides’ lengths, or 15 (it cant be 15 either), so the answer is any number under 15, or (E) 14.</p>
<p>likewise, the 3rd side must be greater in length than the difference (8-7=1)</p>
<p>1<LN<15, the length is E</p>
<p>Well, actually, the highest it can be is 15 and the lowest 1. It’s a less/greater than or equal to. This is because this problem in context does not explicitly say it must be a triangle. Therefore, you can simply make a line segment of L M N, or N L M. The answer is still E though.</p>
<p>Thanks guys!</p>