1. "Careful, now," Ann warned the boy, handing him the paper bag. "You get 5p each for returning the empties, and full bottles are 31p each. Get litres, remember, the same as these." "Fine, Mum," Sam replied. "But how many empties did you put in?" "Oh not many - there can't be more than ten there," Ann told him. "And here's 68p, the difference you'll have to pay." How many full bottles did Sam have to buy?

2 bottles

4 bottles

3 bottles