Question

A consignment of 25 auto batteries, 3 are defective. If a random sample of 5 batteries is selected, the
probability of having exactly 2 defective batteries in the sample is?
a) 5.3%
b) 3.5%
c) 12.0%
d) 8.7%​

Answer 1

Answer:

Correct option is

D

None of these

Here at least 2 items are defective out of 4. So the no. of defective items can be 2 or defective can be 3.

Total no. of defective ites =3

If 2 items are defective =

3

C

2

×

7

C

2

=63

If 3 items are defective =

3

C

3

×

7

C

1

=7

Probability that atleast 2 out of 4 items are defective =

10

C

4

63+7

=

210

70

=

3

1

Answer 2

Answer:

monolith is a geological feature consisting of a single massive stone or rock, such as some mountains. Erosion usually exposes the geological formations, which are often made of very hard and solid igneous or metamorphic rock.