Quantitative Aptitude - Arithmetic Ability Questions

Coefficient of x in (x + 9)(8 - 5x) is

In a triangle PQR, ∠Q = 90°. If PQ = 12 cm and QR = 5 cm, then what is the radius (in cm) of the circum circle of the triangle?

If Cot θ = 24/7, then Sin θ = ?

The distance between two pillars is 120 metres. The height of one pillar is thrice the other. The angles of elevation of their tops from the midpoint of the line connecting their feet are complementary to each other. The height (in metres) of the taller pillar is (Use : √3 = 1.732)

In the following question, select the missing number from the given series.
 
1912, 2012, 2133, 2277, 2446, ?

If (x - 13)2 + (y - 4)2 = 0, then the value of y + xy - x ?

What is the difference of the factors of the expression x2 + (1/x2) – 6?

If k is the largest possible real number such that p4+q4=(p2+kpq+q2)(p2-kpq+q2),then the value of k is