5 What simple interest rate will Susan need to secure to make 2500 in interest on a 10000 principal over 5 years?

since its not compounded this is a very simple problem.

r= interest rate

x= principle

y=years

Interest Accumulated = x*y*r

so, in your case:

2500 = 10000 * 5 * r

2500 = 50000r

divide both sides by 2500

and you get: r=.05 (or 5%)