Question

There are 30 blue balls and x red balls in a
bag. A ball is drawn at random from the bag.
(1) Write down, in terms of x, an expression
for the probability that the ball drawn is
red.
(ii) Given that the probability is
find x.​

Answer 1

Answer:

Blue balls =30

Red balls =x

Total balls =30+x

Probability of red balls =

30+x

x

According to question,

30+x

x

=

13

7

⇒13x=210+7x

=6x=210

x=35