5 cents.

The bat costs $1.05 and the ball costs $0.05:
1.05 + 0.05 = 1.10

This question was in the 31st October issue of the New Scientist magazine on page 38. There were also two other questions printed with it:

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

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?

????

@Simo, people who usually calculate mentally will first arrive at an answer of $0.10, but wondering why this question was posed, they will then possibly arrive at $0.05.

However, some people who calculate on paper will get the correct answer straight away.

a. 5 minutes?
b. 47 days

If it's wrong whichever way, how can someone get it as the right answer?
Kizungu ngumu sana.

Remember this:
1. How do you put a giraffe into a refrigerator?
Correct Answer: Open the refrigerator, put in the giraffe, and close the door.

2. How do you put an elephant into a refrigerator? Did you say, Open the refrigerator, put in the elephant, and close the refrigerator?
Correct Answer: Open the refrigerator, take out the giraffe, put in the elephant and close the door.

3. The Lion King is hosting an animal conference. All the animals attend.... except one. Which animal does not attend?
Correct Answer: The Elephant. The elephant is in the refrigerator.

4. There is a river you must cross but it is used by crocodiles, and you do not have a boat. How do you manage it?
Correct Answer: You jump into the river and swim across. Have you not been listening? All the crocodiles are attending the Animal Meeting.

Children in elementary school will generally score 3 or 4 in this test

But, adults score 0 because they calculate too much, and hence drift off the logic.

E.g., someone scored 0/4 because his first answer was that a giraffe is too large to fit in a refrigerator

I have concluded mimi ni kichwa uji na ninaoba thirikari iigirie hii maneno ya saitani.

Yeah, and guka you are right, one must have an analytical head......si mambo ya kusema open the door, put the girrafe in and close the door...how now, you can fail a job interview for being such an ABK.....you must 1st ask for the parameters of the girraffe and the fridge!!!!

even simpler...if they are left to share 0.10, then each gets 0.05 and the one with $1 more is added his.no need for pen and paper

You are both wrong. Without further specifics you cannot rule out that possibility however analytical you claim to be.

They did not specify what type of refrigerator, whether normal or not. Last I checked there is no limit on the size of a refrigerator (like if someone made one the size of an elephant it stops being a refrigerator) and nothing stops one from making a big enough refrigerator to fit a giraffe or an elephant.