Question

B) In a box of 10 oranges, 3 are bad. If two oranges are drawn at random one after the other

without replacement, find the probability that
(i)both are good
(ii)one is good and the other is bad
​

Answer 1

Answer:i

i) 7/15

ii) 7/15

Explanation:

total: 10

good: 7

bad: 3

i) both are good

p(both good) = 7/10 * 6/9 = 42/90 = 7/15

ii) one good & one bad

p(first good & second bad) = 7/10 * 3/9 = 21/90 = 7/30

p(first bad & second good) = 3/10 * 7/9 = 21/90 = 7/30

p(one good & one bad) = 7/30 + 7/30 = 14/30 = 7/15

Answer 2

Explanation:

Let A,B, and C be the respective events that the first, second, and third drawn orange is good.

Therefore, probability that first drawn orange is good, P(A)=

15

12

​

The oranges are not replaced.

Therefore, probability of getting second orange good, P(B)=

14

11

​

Similarly, probability of getting third orange good, P(C)=

13

10

​

The box is approved for sale if all the three oranges are good.

Thus, probability of getting all the oranges good =

15

12

​

×

14

11

​

×

13

10

​

=

91

44

​

=0.48

Therefore, the probability that the box is approved for sale is 0.48