Question 25000
It will help if you have a calculator and know how to use it.
The formula for compound interest is:
  A = P(1+r/n)^(nt)
For your compound interest problems P=$10,000,
r = 0.1; you are given a value for n for each problem;
t=2.  Plug in those values and find "A" for each value of n.
For the continuous compounding use the formula.
For the $15000 situation you have the following
15000=10000e^(0.1t)
1.5 = e^(0.1t)
Take the natural log of both sides to solve for "t".
ln (1.5) = 0.1t
t = [ln(1.5)] / 0.1
I don't have a calculator with me so I'll leave this to you.

Cheers,
stan H.