Quantitative Aptitude - Arithmetic Ability Questions

In triangle PQR, C is the centroid. PQ = 30 cm, QR = 36 cm and PR = 50 cm. If D is the midpoint of QR, then what is the length (in cm) of CD?

A batsman scores 87 runs in the 21st match of his career. His average runs per match increases by 2. What was his average before the 21st match.

To travel 672 km, an Express train takes 14 hours more than Rajdhani. If however, the speed of the Express train is doubled, it takes 8 hours less than Rajdhani. The speed of Rajdhani is

What is the remainder when 6910 is divided by 81?

If xy = -30 and x2 + y2 = 61, then find the value of (x + y).

If p/q = (x+3)/(x-3), then what is the value of p2+q2p2-q2 ?

9997 x 10003 = ?

The area of the largest sphere ( in cm2) that can be drawn inside a square of side 18 cm is