What is more useful when it is broken?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

In a supermarket, there is an intelligent glass pane before a refrigerating unit. This glass pane allows cherries and apples through it but does not allow grapes and Orange to pass through it.

Can you identify the rule that the glass pane is following?