A spider builds a web in a garden. The position vectors of the ends A andB relative to an origin O of a strand of the web are given by OA = 2i + 3j + k and OB = 3i + 4j + 2k. Another web strand MN has end points M and N with position vectors OM = 4i + 2j - k and ON = 6i + 10j + 9k. The spider decides to continue AB to join MN. Find the position vector of the point of contact.
I worked out AB to be i + j + k, but I don't know where to go from there. We've just started vectors so most of this is new to me.