Question

From a box containing $20$ tickets of value $1$ to $20$, four tickets are drawn one by one. After each draw, the ticket is replaced. The probability that the largest value of tickets drawn is $15$ is

• A. $(\frac{3}{4}{)}^4$
• B. $\frac{27}{320}$
• C. $\frac{27}{1280}$
• D. None of these

Answer 1

Answer: (B)

$\frac{27}{320}$

We need to pick $15$ and $3$ numbers less than or equal to $15$.
Required probability = $\frac{1\times 15\times 15\times 15}{20\times 20\times 20\times 20}=\frac{27}{320}$