PLZ HELP PLZ

1  There are  11 possible rolls   2 - 12      only 4 and 9 are perfect squares    so   2 / 11

2   there are 28 odd cards (if you consider jacks and kings as odd cards)   there are 13 spades (seven of which are already counted as odd cards) so 6 more possibilities       28+6  /  52  = 34/52 = 17/26   

3

p    n      d          total

h    h      h            16

h    h      t               6

t     t       h             10

t     t       t                0

h    t       h             11

t     h      h             15

h    t       t                1 

t     h      t                5                   I THINK there are 8 possibilities    5  total at least 6 cents      5 out of 8    or  5/8

Don't want to tackle #4  #5

Hi Electric Pavlov,

I'm going to have a go too :)

1) 2 standard 6-sided dice are rolled. What is the probability that the sum rolled is a perfect square?
ElectricPavlov has nailed it!

2) A card is drawn at random from a standard 52-card deck. What is the probability it is an odd number or a spade?

This one can be interpreted differently so it is a bad question....

I am going to consider odd numbers to be 3,5,7,9    there are 4*4=16 of these

There are 13 spaces and there are 4 odd spades so

P=(16+13-4)/52 = 25/52

3) A penny=1, nickel=5, and dime=10 are simultaneously flipped. What is the probability that heads are showing on at least 6 cents worth of coins?

dime and any other=0.5       nickel and penny but not dime= 0.5*0.5*0.5 = 0.125

So the prob will be  0.625   or  5/8

AGAIN ElectricPavlov nailed it!   :)

4) 8 coins are simultaneously flipped. What is the probability that heads are showing on at most 2 of them?

P(none)+P(1head)+P(2heads)

\(= 8C0 * 0.5^8 + 8C1 * 0.5^8 + 8C2 * 0.5^8\\ = 1 * 0.5^8 + 8 * 0.5^8 + 28 * 0.5^8\\ = (1+8+28) * 0.5^8 \\ = 37* 0.5^8 \\\)

37*0.5^8 = 0.14453125

5) 5 white b***s and k black b***s are placed into a bin. Two of the black b***s are drawn at random. The probability that one of the drawn b***s is white and the other is black is .

\(\mbox{P(one white and one black)=}2(\frac{5}{5+k}*\frac{k}{5+k})=\frac{10k}{(5+k)^2}\)

Please ask if you would like more explanationg :)

Hi Miss Melody,

Why isn't the answer to #5 a probality of zero?  How can one ball be white If two of the black b***s are drawn? 

The $#&^#%^* network will not let me log on. 

GA

1- http://www.wolframalpha.com/input/?i=2+6-sided+dice+tossed,+total+4

2-http://www.wolframalpha.com/input/?i=2+6-sided+dice+tossed,+total+9

How are these different from your calculations? would you add them up: 1/12 + 1/9=7/36?????????.

1) 2 standard 6-sided dice are rolled. What is the probability that the sum rolled is a perfect square?

The possible perfect squares are 4 and 9

A "4"  can be obtained in 3 ways

A "9" can be obtained in  4 ways

And the total number of outcomes = 36   so.......

The probability of a perfect square being rolled  =  [ 3 + 4 ] / 36 =    7/36

1) In dice tossing, where the desired outcome is some sum of the dice tossed, the probability is ALWAYS equal to the coefficients of this generating series divided by 6^n, where n=number of tosses or number of dice tossed: expand [n+n^2+n^3+n^4+n^5+n^6]^2

=n^12+2 n^11+3 n^10+4 n^9+5 n^8+6 n^7+5 n^6+4 n^5+3 n^4+2 n^3+n^2
(11 terms). So the coefficient of n^4=3, and the coefficient of n^9=4.

Therefore, the total probability is: (3+4)/6^2=7/36, or =~ 19.44%.