Use guess and check to solve these problems.
1. Jane bought 2 stone games from Matthew. Together the games cost 48 pence. One game cost 12 pence more than the other. How much did each game cost?
2. Caroline and Catherine walked for 52 minutes altogether. Caroline walked 8 minutes longer than Catherine. How long did Caroline walk?
3. Hugo invited his friends to play chess for his birthday. He invited 7 friends in all. There were 3 more boys than girls. How many girls were there?