One boy forgot the lastdigit of a 7 digit telephone no. If he randomly dialthe final 3 digits after correctly dialing the 1st four, then what is the chance of dialing the correct no.?  Choose the correct choice from the following:
A) 2/995
B) 1/998
C) 1/1000
D) 1/1100
E) 1/1200
it is given that last 3 digits are randomly dialed   Then, each of the digit can be selected out of 10 digits in 10 ways. Hence, required probability   = 1/(10)3 = 1/1000   1/1000
<result>C</result>
One boy forgot the lastdigit of a 7 digit telephone no. If he randomly dialthe final 3 digits after correctly dialing the 1st four, then what is the chance of dialing the correct no.?