Let 'N' is the smallest number which divided by 13 and 16 leaves respective remainders of 2 and 5.Required number = (LCM of 13 and 16) - (common difference of divisors and remainders) = (208) - (11) = 197.
Two balls can be drawn from 18 balls in 18C2 Ways, ie 153 ways. One white from 8 white balls can be drawn in 8C1 = 8 ways and one black ball from 10 black can be drawn in 10C1 = 10 ways.∴ n(S) = 153, n(E) = 8 x 10 = 80∴ P(E) = 80/153
EXAMIANS