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

Options

A. `(81)/(100)`
B. `(82)/(101)`
C. `(19)/(100)`
D. `(19)/(101)`

Answer

A

Explanation

Let the sum of money be x Rs and y paise. Then, y can take the following values :
01, 02,..,99
Therefore, round off error in least ten paise if it is
`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 `=(81)/(100)`