Dialling a telephone number to his daughter an old man forgets the last two digits and dialled at random remembering only that the last two digits are different. The probability that the number dialled is correct is:
(a) 1/10
(b) 1/45
(c) 1/90
(d) 1/135
Dialling a telephone number to his daughter an old man forgets the last two digits and dialled at random remembering only that the last two digits are different. The probability that the number dialled is correct is:
(a) 1/10
(b) 1/45
(c) 1/90
(d) 1/135