Question 1

If two standard dice are rolled. What is the probability that the total of two dice is less than 6?

Accepted Answer

less than 6 would not include 6 so 
[  ‎ ‎  ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ]
| ‎ ‎   1-1‎ ‎ ‎   2-1 ‎ ‎   3-1 ‎ ‎   4-1  ‎ ‎   |
|  ‎ ‎  1-2 ‎ ‎   2-2  ‎ ‎  3-2 ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎|
|  ‎ ‎  1-3  ‎ ‎  2-3 ‎ ‎  ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎     |
| ‎ ‎   1-4 ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎|
[ ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ‎ ‎    ]

Length=10
total =6x6

⁂ p()=10/36

Question 2

A card is drawn from a standard deck of 52 cards. Find the probability that is
a.) a heart or a face card.
b.) a jack or an ace card
c.) a 10 or a spade.

Accepted Answer

I am just warning you, I don't know much about cards that much, so my numbers may be off.
a. there are 13 heart cards and 12 face cards (aces aren't faces, right?), of which 3 are repeated, so 13+12-3 = 22/52 = 11/26
b. there are 4 jacks and 4 aces, so 4+4 = 8/52 = 4/26 = 2/13
c. there are 4 tens and 13 spades, and one 10 is repeated, so 4+13-1 = 16/52 = 8/26 = 4/13
I hope that helps!

Question 3

im hungry 🍞

Accepted Answer

me too😁

Question 4

Can't you multiply the possibility(fraction) with the the same numerator or denominator to get a different but equivalent answer?
Example: 3/4 chance times 3/3(numerator) equals 9/12. At my school, they say you can multiply fractions with the same numerator/denominator, but I haven't taken probability yet in my grade.

Accepted Answer

Yes you can multiply probabilities with fractions that are equal to one. We usually want the fraction in the simpliest form though.

Question 5

does probability always have to be written like a fraction? How do you know when to write it as a percentage?

Accepted Answer

Usually, the question concerning probability should specify if they want either fractions or percentages. Here on KA, you can tell if they're asking for a percentage if you see a % sign by the answer box, while for fractions / decimals a small dialogue box will pop up after you click on the answer box telling you which form to put it in. (I've also seen them state which form to use in italics right after the question.)

Hope this helps!😀

Hope this helps!😀

Question 6

If there were 3 black dogs,4 brown dogs,and 2 white dog what would happen if You took 2 brown dogs away.

Accepted Answer

Um...there would be 7 dogs instead of 9. And there would only be 2 brown dogs now. Which is equal to the number of white dogs. Or is there a more complex reason to this? I don't know. Anyway I hope this helps.

Question 7

Ok, I think I get it. So, would the probability of picking a yellow marble be 37.5%? I got 37.5% by turning 3/8 into a percentage. If I'm correct, this is a lot easier than I thought.

Accepted Answer

Yes that would be indeed correct!

Question 8

3 red marbles and 3 blue marbles. do not replace first marble in bag before picking again.  probability that both marbles are blue

Accepted Answer

There are 6 marbles in total, and 3 of them are blue, so the probability that the first marble is blue is 3∕6 = 1∕2

Given that the first marble was blue, there are now 5 marbles left in the bag and 2 of them are blue, and the probability that the second marble is blue as well is 2∕5

So, the probability that both marbles are blue is 1∕2 ∙ 2∕5 = 1∕5

Statistics and probability

Course: Statistics and probability > Unit 7

Probability: the basics

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