A merchant marks his goods at Rs. 900 and allows a discount of 25%. If he still gain 12.5%, then the cost price of the article is

Direction (66-70): What should come in place of the question mark(?) in the following number series?

7, 8 , 17, 42, ?

$$ {Cos^4θ +Sin^4θ}={2 \over3} $$ then the value of $$ {Cos^2θ -Sin^2θ+1}$$?

A tap takes 36 hours extra to fill a tank due to leakage equivalent to half of its inflow. The inflow can fill the tank in how many hours?

When you see the mirror image of a clock, it shows 11 to 20 minutes in it, then what is the actual time of the clock.

A hexagon is inscribed in a circle of radius 14 cm, three of its alternates sides are 22 cm and each and other sides are equal find the length of other three sides?