Question

A sum of money is rounded off to the nearest rupee. The probability that the error occurred in rounding off at least $15$ paise is

• A. $\frac{29}{101}$
• B. $\frac{29}{100}$
• C. $\frac{71}{101}$
• D. $\frac{71}{100}$

Answer 1

Answer: (D)

$\frac{71}{100}$

An error of at least $15$ paise can occur in the following cases:
Rs $10.15=>Rs10$
Rs $10.16=>Rs10$
...
Rs $10.49=>Rs10$
Rs $10.50=>Rs11$ or Rs $10$ depending on x is even or odd
Rs $10.51=>Rs11$

...
Rs $10.85=>Rs11$
So, error can come from $15$ to $85$ i.e. 71 cases out of 100 => probability = 0.71