arrow
arrow
arrow
There are two children in a family. If it is given that at least one of them is a boy, what is the probability that both the children are boys?
Question

There are two children in a family. If it is given that at least one of them is a boy, what is the probability that both the children are boys?

A.

34\frac{3}{4}

B.

23\frac{2}{3}

C.

13\frac{1}{3}

D.

14\frac{1}{4}

Correct option is C

Step 1: Total possible outcomes

For two children, each child can either be a boy (B) or a girl (G). The total outcomes are:
{BB,BG,GB,GG}\{BB, BG, GB, GG\}
There are 4 total outcomes.

Step 2: Favorable outcomes (at least one boy)
If at least one of the children is a boy, we exclude the outcome GG . The remaining outcomes are:
BB, BG, GB
There are 3 favorable outcomes.

Step 3: Probability formula
The probability that both children are boys, given that at least one of them is a boy, is:
P(both boys | at least one boy)=Favorable outcomes for both boysTotal favorable outcomesP(\text{both boys | at least one boy}) = \frac{\text{Favorable outcomes for both boys}}{\text{Total favorable outcomes}}

Step 4: Calculate the probability
The only outcome where both children are boys is BB . Thus, the number of favorable outcomes is 1 :
P(both boys | at least one boy)=13P(\text{both boys | at least one boy}) = \frac{1}{3}

Final Answer:

The probability that both children are boys, given that at least one of them is a boy, is:
13\frac{1}{3}

Free Tests

Free
Must Attempt

Government Policies and Scheme

languageIcon English
  • pdpQsnIcon10 Questions
  • pdpsheetsIcon20 Marks
  • timerIcon5 Mins
languageIcon English
Free
Must Attempt

Government Schemes

languageIcon English
  • pdpQsnIcon10 Questions
  • pdpsheetsIcon20 Marks
  • timerIcon5 Mins
languageIcon English
Free
Must Attempt

SSC GD PYP (Held on 4 Feb 2025 S1)

languageIcon English
  • pdpQsnIcon80 Questions
  • pdpsheetsIcon160 Marks
  • timerIcon60 Mins
languageIcon English
TEST PRIME

Access ‘Allahabad High Court Group C’ Mock Tests with

  • 60000+ Mocks and Previous Year Papers
  • Unlimited Re-Attempts
  • Personalised Report Card
  • 500% Refund on Final Selection
  • Largest Community
1 month
students-icon
368k+ students have already unlocked exclusive benefits with Test Prime!
TEST PRIME

Access ‘Allahabad High Court Group C’ Mock Tests with

  • 60000+ Mocks and Previous Year Papers
  • Unlimited Re-Attempts
  • Personalised Report Card
  • 500% Refund on Final Selection
  • Largest Community
1 month
students-icon
368k+ students have already unlocked exclusive benefits with Test Prime!
Our Plans
Monthsup-arrow