probability?

Question

A bag contains 5 red marbles, 7 blue marbles, and 10 green marbles. One marble is drawn at random. What is the probability that it will be either:

a. red or green?
b. blue or green?
c. red or blue?

Answer 1

These questions are equivalent to asking

a) what is the probability it is not blue?
b) what is the probability it is not red?
c) what is the probability it is not green?

And the answers are therefore (1- the probability that it is the specified colour)

a) 1-7/22 = 15/22
b) 1-5/22 = 17/22
c) 1-10/22 = 12/22 = 6/11

Answer 2

Hi!! Well, all the answers are correct but what they did not tell you is why they are right. If you knew the why you may not be asking us for help!!! I hope I can explain the why so you can learn this for good!! Here it goes!! Probability in this specific case boils down to this: How many items meet the condition out of the total number of items. In your example, question a asks for the condition of being red or green. We have 5 red and 10 green for a total of 15 marbles that meet your condition. There is a total of 22 marbles in all so your probability of pulling a red or green marble is 15 out of 22. The slash is used in place of the term "out of" so you see it as 15/22 but I always think of it as x out of y - it seems easier for me to remember it that way!! For question b, you need blue or green so 7 blue and 10 green equal 17 that match your condition out of 22 total so you end up with 17/22. Question c is the same. 5 are red, 7 are blue so you end up with 12 out of 22 or 12/22. Now be careful here because I always had to put the answer in the smallest terms so we can reduce answer c to 6/11 by dividing out 2 from the numerator and denominator. Check with your teacher to see which way is acceptable for you to turn in!! To sum it up remember this formula for probability: P ( probability of doing something) is equal to N ( number of items that match what you are doing) divided by T ( the total number of items). P=N/T. Good Luck!!

Answer 3

When u have this kind of question ask yourself the fallowing?

a) what is the probability it is not blue?
b) what is the probability it is not red?
c) what is the probability it is not green?

If we consider 1 = 100% - the probability that it is the specified color.

a) 1-7/22 = 15/22
b) 1-5/22 = 17/22
c) 1-10/22 = 12/22 = 6/11

Good luck!

Answer 4

Not very hard if you're just worried about choosing one marble.

Total marbles are 22. Call the probability that the one (and only one) marble picked is of color x, "P(x)":

P(red) = 5/22
P(green) = 10/22
P(blue) = 7/22

a) P(red or green) = P(red) + P(green) = 15/22.
b) P(blue or green) = P(blue) + P(green) = 17/22.
c) P(red or blue) = P(red) + P(blue) = 12/22.

Answer 5

If red=5 blue=7 green=10

a) red or green
=5+10 /5+7+10

b) blue or green
=7+10 /5+7+10

c) red or blue
=5+7 /5+7+10

Answer 6

(a) 15/22
(b) 17/22
(c) 12/22

Answer 7

a) p(r U g) = p(r) + p(g) - p(r ^ g)
p(r) = (5/22)*(4/21)
p(g) = (10/22)
p(r ^ g) = (5/22)*(10/21)*2
proceed others same like this

Answer 8

a. 15/22
b. 17/22
c. 12/22

Answer 9

a. 15/22
b. 17/22
c. 12/22