Expert: Sherman D. - 3/29/2005

Question
Please HELP.  I can't figure it out.

I need some help in math.  I don't know what to do on these problems.  

Alfonso invested $2400 in an account that pays 3.5% interest, compounded annually and $1600 in an account that pays 4% simple interest.  Find the amount he will have in each account in 13 years?

A tank can be filled in 10 hours and emptied in 12 hours.  One day while filling the tank Sam accidently left the drain open.  After two hours she noticed the mistake and closed the drain.  How long did it take to fill the tank that day?

The number of ounces in a cylindrical can is jointly proportional to it's height and the square of the radius of its base.  If a can with a radius of 4 inches and a height of 8 inches holds 10 ounces, find the number of ounces in a can that is 10 inches high with a radius of 3 inches.  Use principles of variation to solve.

Thank you sooooooooo much!

Answer
A = P(1 + (r/n))^nt
A = 2400(1 + ((.035)/1)))^(1 * 13)
A = 2400(1 + .035)^13
A = 2400(1.035)^13
A = 2400(1.56395606)
A = 3753.494545
or
A = $3,753.49

-----------------

A = PRT
A = (1600)(.04)(13)
A = 1600(.52)
A = $832

So to answer your question, $3753.49 and $832

-----------------------------------------------------------

y = hrk

y = ounces
h = height
r = radius

y = h(x^2)

y = 10
x = 4
h = 8

10 = 128k
k = (5/64)

y = 10(3^2)k
y = 10(9)(5/64)
y = 90(5/64)
y = 450/64
y = 7.03125 ounces

i'm not totally certain if this is correct, since it has been awhile since i did problems like these.