Answer:
1st problem: b) 
2nd problem: c) 
Step-by-step explanation:
1st problem:
The formula/equation you want to use is:

where
t=number of years
A=amount he will owe in t years
P=principal (initial amount)
r=rate
n=number of times the interest is compounded per year t.
We are given:
P=2500
r=12%=.12
n=12 (since there are 12 months in a year and the interest is being compounded per month)

Time to clean up the inside of the ( ).


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2nd Problem:
Compounded continuously problems use base as e.

P is still the principal
r is still the rate
t is still the number of years
A is still the amount.
You are given:
P=2500
r=12%=.12
Let's plug that information in:
.
0.618 divided by 1.03 will equal to 0.6
Answer:
x =27
Step-by-step explanation:
3x - 4y=65
lets substitute the value of y in the equation:
3x -4(4) =65
3x = 65 +16
3x= 81
x= 81/3
x = 27
Answer:
186
Step-by-step explanation:
The formula for volume is Length x width x height.
Bottom: 18 * 12 * 8 = 1728 cubic centimeters.
Middle: 12 * 8 * 6 = 576 cubic centimeters.
Top = 4 *4*4 = 64 cubic centimeters.
Total: 1728 + 576 + 64 = 2368 cubic centimeters.