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
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
add(multiply(divide(8, add(10, 8)), divide(subtract(8, const_1), subtract(add(10, 8), const_1))), multiply(divide(10, add(10, 8)), divide(subtract(10, const_1), subtract(add(10, 8), const_1))))