Assuming that the balls are not replaced;

= 5/42
(the numbers are decreasing in the denominator as you are presumably taking out the red balls. In the denominator, there is one less ball each time since you took out a red one).
Therefore, the probability of selected 4 red balls consecutively without replacement is 5/42.
Hope I Helped :)
The surface area of a sphere is

where r is the radius;
The circumference is

so that

using this value we can evaluate the surface area of 1 ball as:

For 100 ball you get:
8 / 2 = 45 / x....8 servings to 2 cups = 45 servings to x cups
cross multiply
(8)(x) = (2)(45)
8x = 90
x = 90/8
x = 11 1/4 (or 11.25) cups of flour are needed <==
12.072 is irrational because it cannot be simplified into a fraction or ratio.
Hello,
So we can first assign HD videos and classic videos to specific variables, x is HD videos and y is classic videos.
Fiona bought 5 HD videos, and 2 classic videos for 31 dollars.
5x + 2y = 31
Iliana bought 3 HD videos and 5 classic videos for 30 dollars.
3x + 5y = 30
Therefore, the final answer is choice D, 5x + 2y = 31 and 3x + 5y = 30.