If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.
How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

Only one color, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

What Adam and Eve do not have but the rest of the people have?

Find the next number in the sequence

1, 2, 6, 21, 88, __?

Can you find out the missing number in the grid?

How many words can a pen with half refill write?

Can you place three balls such that the equation shown in the picture holds true?

Where do fish keep their money?