Question

22. A bag contains 8 white balls and 4 Ted balls. Five balls are drawn at
random. What is the probabity that 2 of them are red and 3 white?
a)0.424
b)0.858
c)0.748
d)0.699​

Answer 1

Answer:

No. of red or white balls in bag is 13 (5 red and 8 white)

Therefore,

13

C

1

( Selecting 1 out of 13 items) times out of

20

C

1

( Selecting 1 out of 20 items) a red or white ball is picked.

Let E be the event of drawing a red or white ball from bag

We know that, Probability P(E) =

(Total no.of possible outcomes)

(No.of favorable outcomes)

=

20

C

1

13

C

1

=

20

13

Solution(ii):

No. of non-black balls in bag is 13 (5 red and 8 white)

Therefore,

13

C

1

( Selecting 1 out of 13 items) times out of

20

C

1

( Selecting 1 out of 20 items) a non-black ball is picked.

Let E be the event of drawing a non-black ball from bag

We know that, Probability P(E) =

(Total no.of possible outcomes)

(No.of favorable outcomes)

=

20

C

1

13

C

1

=

20

13

Solution(iii):

No. of neither black nor white balls in bag is 5 (5 red balls)

Therefore,

5

C

1

( Selecting 1 out of 5 items) times out of

20

C

1

( Selecting 1 out of 20 items) a neither white nor black ball is picked.

Let E be the event of drawing neither white nor black ball from bag

We know that, Probability P(E) =

(Total no.of possible outcomes)

(No.of favorable outcomes)

=

20

C

1

5

C

1

=

20

5

=

4

1