+91-8076753736 [email protected]

-->

Probability

Question

Wired Faculty App

If the number of square centimetres on the surface of a sphere is equal to the number of cubic centimetres in its volume, what is the diameter of the sphere?

Solution

Let the radius of the sphere be r cm. Then, Surface area = 4πr² cm²
and, volume=

4 over 3 πr cubed space cm cubed

According to the question,

4 πr squared equals 4 over 3 πr cubed

rightwards double arrow space space space space space space space space space space space space space straight r equals 3 rightwards double arrow space space space space space space space space space space space space 2 straight r space equals space 6

Hence, the diameter of the sphere is 6 cm.

Some More Questions From Probability Chapter

The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of र 7.50 per m².

A cubical box has each edge 10 cm and another cuboidal box is 12.5 cm long, 10 cm wide and 8 cm high.

(i) Which box has the greater lateral surface area and by how much?

A cubical box has each edge 10 cm and another cuboidal box is 12.5 cm long, 10 cm wide and 8 cm high.

(i) Which box has the greater lateral surface area and by how much?

A small indoor greenhouse (herbarium) is made entirely of glass panes (including base) held together with tape. It is 30 cm long, 25 cm wide and 25 cm high.

(i) What is the area of the glass?
(ii) How much of tape is needed for all the 12 edges?

Parveen wanted to make a temporary shelter for her car, by making a box-like structure with tarpaulin that covers all the four sides and the top of the car (with the front face as a flap which can be rolled up). Assuming that the stitching margins are very small, and therefore negligible, how much tarpaulin would be required to make the shelter of height 2.5 m, with base dimensions 4 m × 3 m?

Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation