Find the number of rectangles?

_ zy_zxy_yxzx_zyx_sy 

At a college party five girls are sitting in a row. P is to the left of M and to right of O. R is sitting to the right of N, but to left of O. Who is sitting in the middle?

How many quadrilaterals are there in the given figure?

Choose the correct option from the following options.
8 : 9 ∷ 64 : ?

Which of the following numbers will replace the question mark (?) in the given series?

58, 179, ?, 492, 688

In a row of 36 boys, who are facing north, P is eighth from the right end and there are seven children between L and P. What is L's position from the left end of the row?

If ‘+’ stands for division, ÷ stands for multiplication, multiplication stands for addition; then which one of the following equation is correct?