Which figure should replace the question mark (?) if the

Which two signs should be interchanged to make the given equation correct?

39 ÷ 3 − 11 + 45 × 17 = 171 

If a mirror is placed on the line MN, then which of the answer figures is the mirror image of the given figure?

How many triangles are there in the given figure?

In a certain code language, '893' means 'Shahid likes cakes', '137' means 'cakes are delicious', and '274' means 'we are girls'.

Find the next number in the series.

525, 373, 251, 159, 97, ? 

Select the set in which the numbers are related in the same way as are the numbers of the following sets.

What should come in place of the question mark (?) in the given series?

22, 24, 28, 30, 34, ?

In the following question below are given some statements followed by some conclusions based on those statements.

How many such numbers are there in the following string each of which is NOT followed by a symbol?