Question

Ram put some buttons on the table. There were $4\mathrm{blue},7\mathrm{red},3\mathrm{black}$ and $6\mathrm{white}$ buttons in all. All of a sudden, a cat jumped on the table and knocked out one button on the floor. What is the probability that the button on the floor is blue?

• A. $\frac{7}{20}$
• B. $\frac{3}{5}$
• C. $\frac{1}{5}$
• D. $\frac{1}{4}$

Answer 1

The correct option is C

$\frac{1}{5}$

Here

Number of the blue button $=4$

Total number of buttons $=4+7+3+6=20$

We know that

Probability of event to happen

$\mathrm{P}\left(\mathrm{E}\right)=\frac{\mathrm{Number}\mathrm{of}\mathrm{favourable}\mathrm{outcomes}}{\mathrm{Total}\mathrm{Number}\mathrm{of}\mathrm{outcomes}}$

$\Rightarrow$Probability(Blue Button) $=\frac{\mathrm{Number}\mathrm{of}\mathrm{blue}\mathrm{buttons}\mathrm{on}\mathrm{the}\mathrm{table}}{\mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{buttons}\mathrm{on}\mathrm{the}\mathrm{table}}=\frac{4}{20}=\frac{1}{5}$

Hence the correct option is C