Answer:
495 combinations of 4 students can be selected.
Step-by-step explanation:
The order of the students in the sample is not important. So we use the combinations formula to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.
How many combination of random samples of 4 students can be selected?
4 from a set of 12. So
495 combinations of 4 students can be selected.
3/4 (x-12)=12
3/4x - 9= 12
+9 +9
3/4x=21
*3/4 *3/4
x= 15 3/4
and
3/4y-12=12
+12 +12
3/4y = 24
*3/4 *3/4
y= 18
Simple, finding markdown, use these two formulas.
Markdown=Original-New
and
Percent Markdown= Markdown Amount/Original*100
So,
Markdown=612-450
M=162
Markdown%= 162/612*100
M%=0.2647*100
M%=26.5 (rounded)
Thus, there was a 26.5% decrease.
First let us find the slope between the two points.
Slope = Change in y / Change in x.
(3, 6) and (8, 4) compares to (x₁, y₁) and (x₂, y₂)
Slope = (y₂ - y₁) / (x₂ - x₁) = (4 - 6) / (8 - 3) = -2/5
Slope m = -2/5= -0.4
Using y = mx + c, using point (3, 6)
y = -0.4x + c
6 = -0.4*3 + c
6 = -1.2 + c
6 + 1.2 = c
7.2 = c
c = 7.2
Equation = : y = -0.4x +c
y = -0.4x + 7.2
y = -4/10 + 72/10
10y = -4x + 72
5y = -2x + 36
Equation =: 5y = -2x + 36
Hope this explains it.
So, you divide 18 by 12 to get 1.5
but since you want the fraction, just reduce 18/12 as much as possible to get 3/2
