Can you count the number of triangles in the given figure?

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

How many words can a quill made with the feather of a pigeon write with a 100ml bottle of black ink?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

Count the squares in the matchstick puzzle below?

Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation. Conditions: Each must be used exactly once and no other numbers or symbols can be used.

Can you find out the number that should replace the question mark with a valid reason?

Can you count the number of quadrilaterals in the picture below?

Solve the counting riddle by identifying the number of triangles in the given picture.

What happened when the wheel was invented?