Quantitative Aptitude - Arithmetic Ability Questions

The value of cos220°+cos270° is

A racing car going at an average speed of 108 km/hr takes 15 minutes to complete a lap on a racing track. By how much should it increase its speed (inkm/hr) to complete the lap in 12 minutes?

Two numbers are 35% and 50% lesser than a third number. By how much percent is the second number to be enhanced to make it equal to the first number? 

In the given figure, PQR is a triangle and quadrilateral ABCD is inscribed in it. QD = 2 cm, QC = 5 cm, CR = 3 cm, BR = 4 cm, PB = 6 cm, PA = 5 cm and AD = 3 cm. What is the area in sq.cm of the quadrilateral ABCD?

If 2x + 6y = 3xy and 10x -­ 3y = 4xy, find x, y.

To travel 660 km, an Express train takes 10 hours more than Rajdhani. If however, the speed of the Express train is doubled, it takes 7 hours less than Rajdhani. The speed of Rajdhani is

Cost price of 28 articles is equal to Sale price of 21 articles, then percentage of profit is

If a boat goes upstream at a speed of 21 km/h and comes back the same distance at 28 km/h. What is the average speed (in km/hr) for the total journey?