Question

Which of the following can not be the probability of an event ?

• A. $\frac{39}{100}$
• B. $\frac{0.001}{20}$
• C. $\frac{10}{0.2}$
• D. $10\%$

Hint:

Always simplify fractions and percentages first.
Any value greater than $1$ (or $100\%$) or less than $0$ can never represent a probability.

Answer 1

The Correct Option is C

Step 1: Convert every option to a percentage instead of a decimal.
A valid probability must lie between $0\%$ and $100\%$.
Step 2: Convert each option.
(A) $\frac{39}{100} = 39\%$. (B) $\frac{0.001}{20} = 0.005\%$. (C) $\frac{10}{0.2} = 50 \to 5000\%$. (D) $10\%$ is already a percentage.
Step 3: Spot the one outside the valid range.
Only $5000\%$ is far beyond $100\%$, so option (C), $\frac{10}{0.2}$, cannot be a probability.
\[ \boxed{\frac{10}{0.2}} \]