Question

The diagram shows the contents of a jar of marbles. You select two marbles at random. One marble is drawn and not replaced. Then a second marble is drawn. What is the probability of selecting a red marble and then another red marble?

A) 3/64
B) 1)4
C) 1/20
D) 1/30
( there are 7 blue marbles, 5 green marbles, and 4 red marbles)

Answer 1

Since these are dependant, it is 4/16 times 3/15 since you took one out and did not replace. so C, 1/20

Answer 2

Option C is the answer.

Explanation:

There are some marbles in a jar

Blue - 7 marbles

Green - 5 marbles

Red - 4 marbles

Total = 16 marbles

You selected two marbles at random without replacing any.

So the probability that first marble drawn is red =
`(4)/(16)`

Now without replacing you selected another marble, So the probability that second marble is red =
`(3)/(15)`

`P_(1)` =
`(4)/(16)`

`P_(2)` =
`(3)/(15)`

P =
`(4)/(16)` ×
`(3)/(15)` =
`(1)/(20)`

The probability of selecting a red marble and then another red marble is

`(1)/(20)`.

Option C is the answer.