Answer
Tel No. 570 _ _ _ _ _ _ _ _ _
Since tel number cannot start with 0 or 1, so,
Possible tel no.s = 8 x 10 x 10 x 10 x 10 x 10 x 10
= 8 x 10$^{6}$
P(randomly generating cousin’s tel number on the first try) = 1 / 8 x 10$^{6}$
= 1.25 x 10$^{-7}$
Work Step by Step
As given in answer
