How many quadrilaterals are there in the given figure?

Which set of letters when sequentially placed at the gaps in the given letter series shall complete it?
_qr_srq_p_rs_r_p

What is value placed at Question mark?
10.1: 1.01 ::  0.1: ?

Some equations are solved on the basis of a certain system. Find the correct answer for the unsolved equation on that basis.
7– 4 – 1 = 714, 9 – 2 – 3 = 932 8– 0–4 = ?  

Mohan travelled 5 km towards the West. Then he travelled 3 km. after turning to the left, then 9 km. after turning to the right. Then he went 3 km. towards the North. How far is he from the starting point?

Which option will replace the question mark in the following picture series?

In the following questions complete the number series :
204, 100, 48, 22, ___

How many triangles are there in the following figure?