The equation will be of the form:

where A is the amount after t hours, and r is the decay constant.
To find the value of r, we plug the given values into the equation, giving:

Rearranging and taking natural logs of both sides, we get:


The required model is:
Answer:
Catherine's GPA is 2.48
Step-by-step explanation:
A z-score of 2.010 means that Catherine's GPA is 2.01 standard deviations above the mean. Therefore, Catherine's GPA is 
Answer:
50=(3x)x
Step-by-step explanation:
50=(3x)x. The question is only asking for the inequality of the problem. Since the area of a rectangle is L x W, you would write L as 3x and W as x, and since the area of the rectangle is given, you can set the area as 50.
Answer:
28
Step-by-step explanation:
The binomial coefficient is calculated as:

It means that there are nCx ways to select x elements from a group of n elements.
So, If the researcher wants to determine the probability that 6 out of the next 8 individuals in his community are in favor of the president, we can replace n by 8 and x by 6 and calculated the binomial coefficient as:

Answer:
A dress originally costs $120
Step-by-step explanation:
To find the original cost of the dress, we will follow the steps below;
let x represent the original cost of the dress
75% of x = $90
× x = $90
= $90
MULTIPLY both-side of the equation by 100
× 100 = $90×100
At the right-hand side of the equation, 100 will cancel out 100, leaving us with just 75x
75x = $9000
DIVIDE both-side of the equation by 75
75x/75 = $9000/75
At the left-hand side of the equation 75 will cancel-out 75 leaving us with just x
x= $9000/75
x = $120
A dress originally costs $120