Set up the two events
A = first card is a 9
B = second card is a 9

The probability for event A is
P(A) = 4/52
because there are four "9" cards out of 52 total

If event A happens first, and B follows, then the probability is
P(B|A) = 3/51
because there are 3 nines left over out of 52-1 = 51 total left over
No replacement has been made
The notation P(B|A) means "probability of event B given that event A has happened"

Multiply the probabilities
P(A and B) = P(A)*P(B|A)
P(A and B) = (4/52)*(3/51)
P(A and B) = (4*3)/(52*51)
P(A and B) = 12/2652
P(A and B) = 1/221
P(A and B) = 0.00452488687782

Rounded to 4 decimal places, the approximate answer is 0.0045
The exact answer as a fraction is 1/221

7 0

3 years ago

-5=3/4x-2 solve for x and please show your work!

Nookie1986 [14]

-5 = $\frac{3}{4} x$ - 2 equals x = -4.

First, simplify $\frac{3}{4} x$ to $\frac{3x}{4}$ . / Your problem should look like: -5 = $\frac{3x}{4}$ - 2.
Second, multiply both sides by 4. / Your problem should look like: -20 = 3x -8.
Third, add 8 to both sides. / Your problem should look like: -20 + 8 = 3x.
Fourth, simplify -20 + 8 to -12. / Your problem should look like: -12 = 3x.
Fifth, divide both sides by 3. / Your problem should look like: $- \frac{12}{3}$ = x.
Sixth, simplify $\frac{12}{3}$ to 4. / Your problem should look like: -4 = x.
Seventh, switch sides. / Your problem should look like: x = -4, which is your answer.

3 0

3 years ago