-->

Probability

Question
CBSEENMA9003428

What length of tarpaulin 3 m wide will be required to make conical tent of height 8 m and base radius 6m? Assume that the extra length of material that will be required for stitching margins and wastage in cutting is approximately 20 cm (Use straight pi = 3.14)

Solution

For conical tent
h = 8 m r = 6 m
therefore space space space straight l equals square root of straight r squared plus straight h squared end root
space space space space space space space equals square root of left parenthesis 6 right parenthesis squared plus left parenthesis 8 right parenthesis squared end root equals square root of 36 plus 64 end root
space space space space space space space equals square root of 100 space equals space 10 space straight m

∴ Curved surface area = πrl
= 3.14 x 6 x 10 = 188.4 m2. Width of tarpaulin = 3 m
therefore  Length of tarpaulin = fraction numerator 188.4 over denominator 3 end fraction equals 62.8 space m

Extra length of the material required = 20 cm = 0.2 m
∴ Actual length of tarpaulin required = 62.8 m + 0.2 m = 63 m.

Some More Questions From Probability Chapter

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?

A table cover 4 m x 2 m is spread on a table. Find the cost of polishing the top of the table at र40 per square metre of 25 cm table cover is hanging all round the table.

A classroom is 7 m long, 6.5 m wide and 4 m high. It has one door 3 m x 1.4 m and three windows each measuring 2 m x 1 m. The interior wall is to be colour washed. Find the cost of colour washing at the rate of र 3.50 per m2.

Two cubes of side 6 cm each, are joined end to end. Find the surface area of the resulting cuboid.  

The dimensions of a rectangular box are in the ratio of 2 : 3 : 4 and the difference between the cost of covering it with sheet of paper at the rates of र 8 and र 9.50 per m2 is र1248. Find the dimensions of the box. 

The length, breadth and height of a cuboid are 15 cm, 10 cm and 20 cm. Find the surface area of the cuboid.

Mary wants to decorate her Christmas tree. She wants to place the tree on a wooden block covered with coloured paper with picture of Santa Claus on it (see figure). She must know the exact quantity of paper to buy for this purpose. If the box has length, breadth and height as 80 cm, 40 cm and 20 cm respectively how many square sheets of paper of side 40 cm would she require?