A bag contains 10 green and 8 white balls. If two balls are drawn simultaneously, the probability that both are of the same colour is	Choose the most appropriate option:
A) 8 / 15
B) 21 / 44
C) 3 / 5
D) 11 / 15
E) 7 / 15

Rationale: drawing two balls of same color from ten green balls can be done in 10 c ₂ ways . similarly from eight white balls two can be drawn in ⁸ c ₂ ways . p = 10 c ₂ / ¹ ⁵ c ₂ + ⁸ c ₂ / ¹ ⁵ c ₂ = 21 / 44 answer : b
Answer: B