if $\frac{\cos\alpha}{\cos\beta}$=m and $\frac{\cos\alpha}{\sin\beta}$=n , then the value of ($m^{2}-n^{2}$)$\cos^{2}\beta$ is
1). n2
2). m2
3). mn
4). 1
The angle of elevation of the top of a pillar from the foot and the top of a building 20 m high, are 60° and 30° respectively. The height of the pillar is
1). 10 m
2). 10√3 m
3). 60 m
4). 30 m
An article marked at Rs. 540 is sold at Rs. 496.80 in an offseason offer. Then the rate of descount offered (in percent) is
1). 7
2). 7.5
3). 8
4). 10
A train, 200 m long, is running at a speed of 54 km/hr. The time in seconds
that will be taken by train to cross a 175 m long bridge is
1). 12.5
2). 20
3). 25
4). 10
The difference between the greatest and least fivedigit numbers formed by the digits 2,5,0,6,8 is (repetition of digits are not allowed)
1). 69552
2). 65925
3). 65952
4). 63952