When researchers put the following three problems to 3400 students in the US, only 17 per cent got all three right. Can you do any better?

1) A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?

2) If it takes five machines 5 minutes to make five widgets, how long would it take 100 machines to make 100 widgets?

3) In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half of it?

[For answers, see below]

Answers: 1) 5 cents, 2) 5 minutes, 3) 47 days

Source: Shane Frederick, 2005