Question

Suppose a jar contains 20 red marbles and 40 blue marbles. If you reach in the jar and pull out 2 marbles at random, find the probability that both are red. Round to at least 2 decimal places.

Answer 1

Given:

Suppose a jar contains 20 red marbles and 40 blue marbles. If you reach in the jar and pull out 2 marbles at random,

Required:

Find the probability that both are red.

Step-by-step explanation:

We have 20 + 40 =60 marbles in total.

At our first pull,

`\text{ There is an}(20)/(60)\text{ chance that }`

At the second pull ,

`There\text{ is a }(19)/(59)\text{ chance that the second marbel will be red as well.}`

From here, we multiply our two fractions together:

`(20)/(60)*(19)/(59)`

We can do a little bit simplifying first;

`\begin{gathered} =(19)/(177) \\ =0.107 \end{gathered}`

Answer:

0.107 is the probability that both are red.