Q76 / 150 · MHT CET 2022 (07 Aug Shift 2) · Mathematics
A family with three children is chose at random. The probability that the oldest and youngest children are of the same gender is
- A$\frac{3}{8}$
- Correct answerB$\frac{1}{2}$
- C$\frac{1}{8}$
- D$\frac{2}{8}$
Solution
$\mathrm{S}=\{\mathrm{BBB}, \mathrm{BBG}, \mathrm{BGB}, \mathrm{BGG}, \mathrm{GBB}, \mathrm{GBG}, \mathrm{GGB}, \mathrm{GGG}\}$
$\mathrm{E}=\{\mathrm{BBB}, \mathrm{BGB}, \mathrm{GBG}, \mathrm{GGG}\}$
$P(\mathrm{E})=\frac{n(\mathrm{E})}{n(\mathrm{~S})}=\frac{4}{8}=\frac{1}{2}$
Hence, the correct answer is option: 'B'.