A sum of money is rounded off to the nearest rupee. The probability that round off error is at least ten paise is

$\frac{81}{100}$

Let the sum of money be x ₹ and y paise. Then , y can take the following values.

01, 02, ............., 99

Therefore, round off error inpaise can be

00, ± 01, ± 02, ......, ±49, 50

The round off error will be at least ten paise if it is

±10, ± 11, ± 12, ......, ±49, 50

Hence, required probability $=\frac{81}{100}$