What has many keys but can’t open a single lock?

What do you answer even though it never asks you questions?

There is a jar in which there are two types of candies.
20 blueberries and 16 strawberries. You perform the following steps:
1) You take out two candies.
2) If the two candies are of the same flavour, you add a blueberry one otherwise, you add the strawberry one.

You repeat these two steps till there is just one candy remaining in the jar. Which flavoured candy will be left?

John can place six large boxes or nine small boxes into a carton.

Can you find out in how many cartons can he place sixty-six boxes in total?

Four cars come to a four-way stop, each coming from a different direction. They can’t decide who got there first, so they all go forward at the same time. All 4 cars go, but none crash into each other. How is this possible?

In the image given, you can find several triangles. Can you count them all?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

What demands an answer, but asks no questions

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

Which statement is true out of the following?
One statement here is false.
Two statements here are false.
Three statements here are false.