# The ratio of white balls and black balls is 1:2. If 9 gray balls is added it becomes 2:4:3. Then what is number of black balls

#### anil kumar

• Jun 29th, 2006

The ratio is 2:4:3
White balls 6, Black balls 12, Grey balls 9

#### A.Ravi kumar

• Jun 30th, 2006

there r a total of 12 black balls,6 white balls the ratio of white balls to black balls is 1:2given gray 9 ballsthen ratio becomes 2:4:3in 2:4:3 3 indicates 1/3rd of actual.as black's share is 4 it should be 4*3=12.and whites r 2*3=6.

#### m_manic Profile Answers by m_manic Questions by m_manic

• Dec 10th, 2009

No. of black ball is 12.

#### vaishnav namboodiri m, call me bonjo

• Sep 1st, 2019

we know that after addding 9 balls, the ratio havent changed. so the ratio of any ball to the total must be equal or a multiple of it. that is , take the case of black balls. suppose their are x grey balls initially. the ratio of grey balls is 2/(1+2+x ). now after adding 9 grey balls the ratio of black balls is 4/(2+4+3). so compare the ratios, that is 2/3+x and 4/9. for the ratio to be multiple of the previous ratio, x must be zero. hence we come to the conclution mathematically that initially their were 0 grey balls. hence now to find the original number of black balls must be, since we know now the bag contains 9 grey balls only, and its raio being 3,the number of black balls must be the 4*3 that is 12 and the number of white balls being 2*3 that is 6.
hope i cleared ur mind.