Answer:
$4080
Step-by-step explanation:
We have the amount she will pay back, but first, we need to find the Interest accrued.
Simple Interest is given as:

where P = principal
R = rate
T = time taken (in years)
Therefore, the interest on $3,000 at 9% simple interest for 4 years is:

I = $1080
Therefore, the amount she will pay back is:
$3000 + $1080 = $4080
High blood pressure, high cholesterol, and smoking.
Answer:
x = 45 when y = 20 and z = 6
Step-by-step explanation:
The general formula here is y = kx/z²
If x = 24 and y = 6, z = 8, so:
y = kx/z² becomes 6 = k(24)/8², and:
6 1
k = ---------------- = -------------- = 16
24/64 4/64
Then y = 16x/z², and so, if y = 20 and z = 6 (check this!), then:
20 = 16x/36, or 16x = 720, or x = 45
x = 45 when y = 20 and z = 6