Riddle: your grandma wants a 7oz cup of water. she gives you a 5oz and a 3oz how do you get 7oz's.
Answer: fill the five.dump 3oz from the five into the 3oz pithcher leaving two in the five. dump out the 3oz pither. dump the 2oz's from the 5oz pither in to 3oz pither. then fill the five.
you should have seven