Question

how do I know when There is a bag with only red marbles and blue marbles.
The probability of randomly choosing a blue marble is
3
8
.
There are 72 marbles in total in the bag and each is equally likely to be chosen.
Work out how many red marbles there must be.
my question is answered

Answer 1

Answer:

there are 45 red marble

3/8 probability is blue so to make denominator into 72 therefore we multiply numerator and denominator by 9

that gives 27/72

and now that gives us 27 blue marble

and subtract it from 72

therefore we get 45 red marble

thank you

Answer 2

Answer:

Let the number of blue marbles be b

P(blue) = b/72 = 3/8

b = 3×72/8 = 27

Then the number of red marbles = 72 - 27 = 45 Ans