The mean of the following distribution is 18. Find the frequency f of class 19 – 21.

OR

The following distribution gives the daily income of 50 workers of a factory

Draw a triangle ABC with BC = 6 cm, AB = 5 cm and ∠ ABC = 60°. Then construct a triangle whose sides are 3/4 of the corresponding sides of the ∆ ABC.

Prove that:

The diameters of the lower and upper ends of a bucket in the form of a frustum of a cone are 10 cm and 30 cm respectively. If its height is 24 cm, find :

(i) The area of the metal sheet used to make the bucket.

(ii) Why should we avoid the bucket made by ordinary plastic? [Use π = 3.14]

As observed from the top of a 100m high light house from the sea - level, the angles of depression of two ships are 30° and 45°. If one ship is exactly behind the other on the same side of the light house, find the distance between the two ships. [Use 3 = 1.732]