Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Probability

Question:

A coin is biased so that head is 4 times as likely to occur as tails. If X represents the number of heads when coins is tossed 4 times then P(X=2) is equal to :

Options:

$\frac{96}{625}$

$\frac{9}{256}$

$\frac{27}{625}$

$\frac{18}{625}$

Correct Answer:

$\frac{96}{625}$

Explanation:

The correct answer is Option (1) → $\frac{96}{625}$

P(Head) = 4 P(Tail)

$⇒P(H)=\frac{4}{5}$ and $P(T)=\frac{1}{5}$

so $P(X=2)$ for $n=4$ tosses

$≡{^4C}_2(\frac{4}{5})^2(\frac{1}{5})^2=\frac{6×16}{625}=\frac{96}{625}$