40/3 or 13.333333- your welcome
(a) The probability of drawing a blue marble at random from a given box is the number of blue marbles divided by the total number of marbles. We assume that the probability of selecting one of two boxes at random is 1/2 for each box.
... P(blue) = P(blue | box1)·P(box1) + P(blue | box2)·P(box2) = (3/8)·(1/2) + (4/6)·(1/2)
... P(blue) = 25/48 . . . . probability the ball is blue
(b) P(box1 | blue) = P(blue & box1)/P(blue) = (P(blue | box1)·P(box1)/P(blue)
... = ((3/8)·(1/2))/(25/48)
... P(box1 | blue) = 9/25 . . . . probability a blue ball is from box 1
According to empirical rule, the area under the normal distribution or "bell-shaped curve", when plotted as a function of the z-parameter can be defined in terms of percentages.
The z-parameter (or z-score) is defined as

where
x = value of random variable,
μ = the mean,
σ = standard deviation,
The total area under the curve = 1.
The curve below shows that within 2 standard deviations from the mean, the total area under the curve is 95% of the total area.
Answer:
95%
If 1/10 of the tank is filled in 1/5 of an hour, then multiplying both of those by 5 you would get 5/10 of a tank being filled in a full hour, or answer choice A. Hope this helps! By the way, sorry for the incorrect answer a couple years ago :)
Answer:
7
Step-by-step explanation:
75% of 28 is 21.
21 pairs are tennis
So,
28-21=7.
7 pairs left!