Question

There are 3 white marbles and 7 blue marbles in a bag. Jamie will randomly pick two marbles out of the bag without replacing the first marble chosen. What is the probability of Jamie picking two biue marbles?

Answer 1

`7/15` -OR- `0.467`

Explanation:

In total, there are `10` marbles in the bag. Since `7` of them are blue, Jamie has a `7/10` chance of picking a blue marble. (This equals`0.7`)

If Jamie does not replace the blue marble, there are `9` marbles left in the bag and only `6` blue marbles left in the bag. So now his chance of picking a blue marble is `6/9`. (This equals `0.667`)

Now, multiply the two probabilities together:
`7/10`x`6/9` `=` `42/90` `=` `7/15`

-OR-

`0.7`x`0.667` `=` `0.467`