Question

There are some white and black balls in a bag. If I replace one of the black ball with a white ball, the probablity of drawing a white ball is incresed by 0.02. How many balls are in the bag?

Answer 1

well 0.02 is 1/50

Answer 2

so there are 50 in total?

Answer 3

or any multiples of 50?

Answer 4

no

Answer 5

The ratio is 1/50.

Answer 6

So it would be 2/100, or 3/150 and so on.

Answer 7

oh...

Answer 8

But that is not the answer, that is just the probability it got increased to.

Answer 9

say there are 100, 50 black, 50 white,
the probability of white is 0.50
if this becomes
100 , 49black, 51white
the probability of white is 0.51
not what we wont

50, 25b,25w
becomes
50, 24b,26w
probability of white is 26/50 =0.52

so there were originally 50, 25b,25w

Answer 10

yeah , hard to think of the right answer without working

Answer 11

oh, I see. So the total would still be 50.

Answer 12

Thank you.