Answer:
10
Step-by-step explanation:
The current probability of picking a red ball is . When 5 more balls are added, the probability is 3/4. We can write a ratio for this problem:
When using cross multiplication to solve this, you get 3 * 20 = 4(x+5).
60 = 4x + 20
40 = 4x
x = 10 red balls
Answer: Last Option
Step-by-step explanation:
In this case we have a uniform probability. In the graph the horizontal axis represents the possible values of the variable x and the vertical axis represents the probability P(x).
To calculate the probability that x is between 4.71 and 7.4 we calculate the area under the curve.
The horizontal length between 4.71 and 7.4 is:
.
Then notice that the vertical length in this interval is 0.125.
Then the area of a rectangle is:
Where l is the length and w is the width.
In this case we have to:
So