Question

A box contains 12 balls of which some are red in colour . If 6 more red balls are put in the box and a ball is drawn at random the probability of drawing a red ball doubles that what it was before .find the number of red balls in the bag.

Answer 1

18 red balls are left in the box.

Answer 2

$\tt\blue{Answer :-}$

❥let the red balls initially be x

❥probability = x/12

❥after 6 red balls have been added, probability becomes (6+x)/18.

❥now according to the question it becomes twice the initial value.

(6+x)/18 = 2 × x/12

❥solving this we get x = 3.

❥initially there were 3 red balls

$\tt\green{hope\:it\:will\:be\: helpful :)}$