The radius of a cylinder is doubled and its height is halved; then the new volume is :

1. same

2. 2 times

3. 4 times

4. 8 times

The dimensions of a solid metallic cuboid are 9 cm x 8 cm x 3 cm. It is melted and recast into a cube. The edge of the cube so formed is :

1. 6 cm

2. 12 cm

3. 18 cm

4. 24 cm

Statement 1: The volume of a right circular cylinder = Area of cross section (area of circle) x Distance between two circular parallel ends.

Statement 2: Lateral surface area of a closed cylinder is 2πr(r + h) cubic units.

Which of the following options is correct?

1. Both the statements are true.

2. Both the statements are false.

3. Statement 1 is true, and statement 2 is false.

4. Statement 1 is false, and statement 2 is true.

Assertion (A) : The length, breadth and height of an open cuboid are 10 cm, 12 cm and 6 cm respectively. If the thickness is 1 cm, then internal dimensions are 8 cm, 10 cm and 5 cm respectively.

Reason (R) : If l, b and h are the external dimension of an open cuboid of thickness 'x', then its internal dimension are (l - 2x), (b - 2x) and (h - x) respectively.

1. Both A and R are correct, and R is the correct explanation for A.

2. Both A and R are correct, and R is not the correct explanation for A.

3. A is true, but R is false.

4. A is false, but R is true.