Answer:
14
Explanation:
You are told that the line segment MO has a total length of 20.
You are also told that point N is somewhere on that line between M and O. They tell you that the distance from point N to point O is 6. So to find the distance from point N to point M, you just subtract the length of N to O from the total length of the M to O segment.
N to O = 6
<-----M---------------------------------------------------N--------------------O------------------>
M to O = 20
So if M to O = 20 and you subtract the distance of N to O (6), you will get the distance from M to N.