1."Let's see how smart you are," said Roy. "I'll give you 13 questions, and you'll get £2 for every correct answer. But you pay me £3 for every wrong one." Joe nodded. "Okay, Dad, but it will cost you a lot." So they started, and in fact the boy ended up only £1 to the good. How many questions defeated him?

Joe failed on 5 questions

Joe failed on 7 questions

Joe failed on 3 questions