Question

A box contains $20$ electric bulbs, out of which $4$ are defective. One bulb is chosen at random from this box. The probability of getting a defective bulb is ___________.

• A. $\frac{4}{5}$
• B. $\frac{1}{5}$
• C. $\frac{7}{20}$
• D. $\frac{11}{20}$

Answer 1

Answer: (B)

$\frac{1}{5}$

Given:-

Total no. of electric bulbs $=20$

Number of defective bulbs$=4$

To find:- Probability (P) of getting a defective bulb, if one bulb is chosen randomly = ?

Solution:-

$P=\frac{\text{Number of defective bulbs}}{\text{Total number of bulbs}}=\frac{4}{20}=\frac{1}{5}$

Hence, the correct answer is $\frac{1}{5}$ (B).

Answer:- $\left(B\right)\frac{1}{5}$