Q. If two coins are tossed 5 times, then the probability of getting 5 heads and 5 tails is
A) $\frac{63}{256}$
B) $\frac{1}{1024}$
C) $\frac{2}{205}$
D) $\frac{9}{64}$
Explanation
(a)
Probability of getting a head $= \frac{1}{2}$
$ie,\ p = \frac{1}{2}\ \Rightarrow q = \frac{1}{2}$
$\therefore$ Required probability ${{= \ }^{10}C}_{5}\left( \frac{1}{2} \right)^{5}\left( \frac{1}{2} \right)^{5}$
$= \frac{10 \times 9 \times 8 \times 7 \times 6}{5 \times 4 \times 3 \times 2}\ \left( \frac{1}{2} \right)^{10} = \frac{63}{256}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.