A thick card-board is cut into the shape as shown alongside. It is given a full round about its line of symmetry (shown by dotted line). The solid so formed has :

(i) one cone and one cylinder

(ii) two cones only

(iii) two cones and one cylinder

Which of the statements given above is true ?

1. only (i)

2. only (iii)

3. only (ii)

4. (ii) and (iii)

The probability of answering a question correctly is $\dfrac{2}{5}$ and probability of not answering the same question correctly is $\dfrac{x}{15}$. The value of x is :

1. 6

2. 9

3. 15

4. 5

Two tangents are drawn to a circle which touch the circle at points A and B. The maximum distance between the points A and B is :

1. radius of the circle

2. diameter of the circle

3. π × radius of the circle

4. π × diameter of the circle

In the given figure, ac = y units, BC = x units, then the height of DC is :

1. $\sqrt{x + y}$

2. $\sqrt{xy}$

3. $\sqrt{y - x}$

4. $\sqrt{\dfrac{y}{x}}$