Search any question & find its solution
Question:
Answered & Verified by Expert
A coin is tossed three times. What is the probability of getting head and tail (HTH) or tail and head (THT) alternatively?
Options:
Solution:
2467 Upvotes
Verified Answer
The correct answer is:
$1 / 4$
Total possible outcomes, $\mathrm{S}=\{\mathrm{HHH}, \mathrm{HHT}, \mathrm{HTH}, \mathrm{THT}$.
TTH. THH, TTT, HTT $\}$ and desired outcomes E $=\{\mathrm{HTH}, \mathrm{THT}\}$
$\Rightarrow \mathrm{n}(\mathrm{E})=2$ and $\mathrm{n}(\mathrm{S})=8$
Hence, required probability $=\mathrm{P}(\mathrm{E})=\frac{\mathrm{n}(\mathrm{E})}{\mathrm{n}(\mathrm{S})}=\frac{2}{8}=\frac{1}{4}$
TTH. THH, TTT, HTT $\}$ and desired outcomes E $=\{\mathrm{HTH}, \mathrm{THT}\}$
$\Rightarrow \mathrm{n}(\mathrm{E})=2$ and $\mathrm{n}(\mathrm{S})=8$
Hence, required probability $=\mathrm{P}(\mathrm{E})=\frac{\mathrm{n}(\mathrm{E})}{\mathrm{n}(\mathrm{S})}=\frac{2}{8}=\frac{1}{4}$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.