For the following questions answer them individually
The number of ways of arranging 10 different books on a shelf such that two particular books are always together is:
Gandhi Sew bridge has a pole that divides the bridge into two parts in a manner such that the ratio of the larger part to the smaller part is m : n. It is found that the ratio of the length of the bridge to the length of the smaller part is six times the ratio of the length of the larger part to the length of the bridge. Find the value of $$\sqrt{25 + mn(m^2 - 4mn + n^2)}$$.
Consider a trapezium PQRS in which PQ || RS. Point E internally divides RS in equal parts and PQRE forms a parallelogram. The area of triangle PSE is 37 $$cm^2$$. Find the area enclosed by the shape PQRS.
What is the equation of a straight line that has y-intercept 5 and is perpendicular to a straight line joining (2, -3) and (4, 2)?
Two non-intersecting circles. one lying inside the other. are of radii $$r_1$$, and $$r_2$$, and $$r_1$$ > $$r_2$$. If the minimum distance between any two points on their circumferences is s, then the distance between their centres is:
Tom, Suresh and Adil are capable of finishing a task in 2, 4 and 8 hours, respectively. Suresh takes a magic medicine that increases his power by n times. Suresh works together with Tom and Adil to complete the task in less than 1 hour. Find the value of the expression $$n^2 + 2$$ where n is a positive integer.