Question

A box contains some balls whose total weight is 40 kg. There are 10 balls of weight 1 kg each, 5 balls each of weight 2 kg, 5 balls each of weight 2.5 kg and rest of the ball weighing 1.5 kg each. A ball is drawn at random from the box, find the probability that the ball drawn is
(i) of weight 2.5 kg.
(ii) of weight neither 2.5 kg nor 1 kg.
(iii) not of weight 1.5 kg.
​

Answer 1

Answer:

Ans (1)5balls are of weight 2.5kg

probability=5/40=1/8

Anse (3) The number of balls weighing 1.5 kg=20

So probability=20/40=1/2

So probability (not 1.5kg/=1-(1/2)=1/2