Dialling a telephone number to his daughter an old man forgets the last three digits and dialled at random remembering only that they are same.The probability that the number dialled is correct is

\frac{1}{720}

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\frac{1}{10}

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\frac{1}{10^{3}}

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\frac{1}{135}

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Solution

The correct option is B $\frac{1}{10}$
Total cases $= 10 = [0, 0, 0 1, 1, 1 2, 2, 2 3, 3, 3 . . . . . 10, 10, 10]$
Correct case $= 1$
The required probability $= 1 / 10$

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Dialling a telephone number to his daughter an old man forgets the last three digits and dialled at random remembering only that they are same.The probability that the number dialled is correct is

The correct option is B 110Total cases =10=[0,0,01,1,12,2,23,3,3.....10,10,10]Correct case =1The required probability=1/10

The correct option is B $\frac{1}{10}$
Total cases $= 10 = [0, 0, 0 1, 1, 1 2, 2, 2 3, 3, 3 . . . . . 10, 10, 10]$
Correct case $= 1$
The required probability $= 1 / 10$