Math, asked by vansh7821, 11 months ago

A survey of 400 families each having 3 children is conducted . in how many families do you expect (1) 1 boy and 2 girl (2) only girls

Answers

Answered by amitnrw
0

150 Families expected to have 1 boy & 2 Girls in 400 families each having 3 children

Step-by-step explanation:

in a family  having 3 children

0B - 3G  - GGG   ( 1 way)

1B - 2G  can be in 3 Ways  BGG  , GBG  , GGB

2B - 1G  Can be  in 3 Ways  BBG , BGB , GBB

3B  - 0 G  BBB  ( 1 way)

Probability of 1 boy & 2 Girls  = 3/8

out of 400 family  = (3/8)*400 = 150

Probability of Only girls =  1/8

out of 400 family  = 400 /8  = 50

other way :

Probability of boy = 1/2

Probability of Girl = 1/2

P(0) boys  = ³C₀(1/2)⁰(1/2)³ = 1/8

P(1) boys  = ³C₁(1/2)¹(1/2)² = 3/8

P(2) boys  = ³C₂(1/2)²(1/2)¹ = 3/8

P(3) boys  = ³C₃(1/2)³(1/2)⁰ = 1/8

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