The woman is moving at 6mi/hr which means 1mi per 10 minuets because 1 hour = 60 minuets and she is moving 6 mi every 60 minutes which means 1 mi every 10 minuets , same thing for that man 12 mi every hour = 2 mi every 10 minuets , and because of the opposite direction we will add 2 + 1 = 3mi after 10 minuets. I hope that helped u a little bit.