Answer:
52 cards:
26 red and 26 black
P(R) = probability of picking a red card
P(B) = probability of picking a black card
P(R) = P(B) = ¹/₂
If with replacement:
P(R∩B) = (¹/₂)(¹/₂) = ¹/₄
If without replacement:
P(R∩B) = (¹/₂)(²⁶/₅₁) = ¹³/₅₁
8 Balls:
3 red and 5 white
P(R) = probability of picking a red ball
P(W) = probability of picking a white ball
P(R) = ³/₈
P(W) = ⁵/₈
If with replacement:
P(R∩W) ∪ P(W∩R) = (³/₈)(⁵/₈) + (⁵/₈)(³/₈)
= ¹⁵/₆₄ + ¹⁵/₆₄
= ³⁰/₆₄
= ¹⁵/₃₂
If without replacement:
P(R∩W) ∪ P(W∩R) = (³/₈)(⁵/₇) + (⁵/₈)(³/₇)
= ¹⁵/₄₂ + ¹⁵/₄₂
= ³⁰/₄₂
= ⁵/₇
Answer:
c. a: 4
b: 12
c: 9
4x² +12x+9=0
(2x+3)(2x+3)= 0
(2x+3)²=0 {square root both sides}
2x+3=0
2x=-3
x= -3/2
If you solve for x the answer is x<-8
16.5 degrees below the starting temp, whatever that is. If its 0, then -16.5 degrees.
The first equation would be (.5)5-11=-8.5, because the metal has been cooling for 5 hours.
The device that 'aids' in the cooling would be -5-3=-8, because it is a separate variable that cools the metal, so the amount the device cools is independent of the natural cooling amount, and the equation is independent of the natural cooling equation.
You then add -8.5 and -8, because the device has lowered 8.5 degrees and 8 degrees. This equals -16.5 degrees, or a decrease of 16.5 degrees.
