Points L,M and N are collinear.You are given LM = 13 and LN=20. What is a possible value of MN?

Solution
For this case we know that L, M and N are collinear
We also have the following values given:
LM= 13, LN = 20
Then we can do this:
Then we can find MN like this:
MN= 20-13 = 7
And the answer would be
B. 7