A marble is selected at random from a jar containing 5 red marbles, 2 yellow marbles & 3 green marbles. What is the probability that a)the marble is red b)the marble is not yellow
c)the marble is either red or green
d)the marble is neither red nor green

5/11

explanation

Probability here is the chance of selection out of a total. So, we need to first find the total number of marbles.

total

=

5

+

3

+

2

+

1

=

11

So there are  

11

marbles total. The probability that we pick one of the  

3

green marbles out of the  

11

is simply that ratio:

P

green

=

3

11

Same idea for yellow:

P

yellow

=

2

11

The probability of picking either of these colors is simply the sum of their probabilities.

P

green or yellow

=

P

green

+

P

yellow

=

3

11

+

2

11

=

5

11

all it means is function 3