a bag contains 20 balls out of which x balls are red.

1) if one ball is drawn at random from the bag , find the probability that it is not red.

2) if 4 more balls are put into the bag , the probability of drawing a red ball will be 5/4 Times the probability of drawing a red ball in the first case. Find the value of x .

Probability of an event is = no. of favourable outcomes/ total no. of outcomes

1) Total no. of balls= 20
No. of red balls= x
Then number of balls that are not red= 20-x
Probability of not getting a red ball = 20-x/ 20


2) When 4 more red balls are added total no. of balls now becomes 24.
No. of red balls= x+4

Now, the probability of drawing a red ball in the second case= x=4/ 24

Probability of drawing a red ball in first case= x/20
According to the condition given,

x+4/24 = 5/4 X x/20  (' X 'stands for multiplication okay?)
On cross multiplication we get.
2x+8 = 3x
x=8