12 copies of a book were sold for Rs. 1800 thereby gaining cost price of 3 copies. The cost price of a copy of the book is
1). Rs. 120
2). Rs. 150
3). Rs. 1200
4). Rs. 1500
The least six digit number which is a perfect square is
1). 100489
2). 100000
3). 100256
4). 100225
A pilot in an aeroplane at an altitude of 200 m observes two points lying on either side of a river. If the angles of depression of the two points be 45° and
60°, then the width of the river is
1). $(200+\frac{200}{\sqrt{3}})m$
2). $(200-\frac{200}{\sqrt{3}})m$
3). $(400\sqrt{3})m$
4). $(\frac{400}{3})m$
If PQ and PR be the two tangents to a circle with centre O such that ∠QPR = 120° then ∠POQ is
1). 90°
2). 45°
3). 30°
4). 60°
If x = a cosθ+ b sinθ and y = b cosθ- a sinθ, then $x^{2}+y^{2}$ is equal to
1). ab
2). $a^{2}+b^{2}$
3). $a^{2}-b^{2}$
4). 1