Question

A rainy day occurs once in every $10$ days. Half of the rainy days produce rainbows. What percent of all the days do not produce rainbows?

• A. $95$ $\%$
• B. $10$ $\%$
• C. $50$ $\%$
• D. $5$ $\%$

Answer 1

Answer: (A)

$95$ $\%$

Let the total number of days $=x$
Therefore, number of rainy days $=$ $\frac{x}{10}$
Number of days with rainbows $=\frac{1}{2}\times \frac{x}{10}=\frac{x}{20}$
Number of days without rainbows $=x-\frac{x}{20}=\frac{19x}{20}$
$=x-\frac{x}{20}=\frac{19x}{20}$ Per cent of all days with no rainbows $=$ $\frac{\frac{19x}{20}}{x}\times 100$ $\%$ $=95\%$