Quantitative Aptitude - Arithmetic Ability Questions

The average weight of 25 candles is 40 grams. If some candles of weight 50 grams each were removed, then average weight becomes 37.5 grams. How many candles of weight 50 grams each were removed? 

If x+y+z = 1, 1/x + 1/y + 1/z = 1 and xyz = -1, then x3+y3+z3 is equal to

PQR is a right angled triangle in which PQ = QR. If the hypotenuse of the triangle is 20 cm, then what is the area (in cm2) of the triangle PQR?

A truck moves at the speed of 90 km/hr after repairing and moves at the speed of 80 km/hr before repairing. It covers x distance in 8 hours after repairing. How much time (in hours) will it take to cover 4x distance before repairing?

A plane flies a distance of 1800 km in 5 hours. What is its average speed in meters/second?

What should be the average speed of a car to cover a distance of 189 km in 3.5 hours?

In ΔABC, D and E are points on side AB and AC respectively. DE is parallel to BC. If lengths of AD, DB and AE are 8 cm, 4 cm and 12 cm respectively, what is the length of AC?

The original price of a TV set is Rs. 6,000. If the price is discounted by 20% and then raised by 10% for service contract, the price charged by the shopkeeper is