What is the interest rate of each investment?

Question

The annual interest rate on an $18000 investment exceeds the interest earned on a $5000 investment by $1148. The $18000 is invested at a 0.6% higher rate of interest than the $5000. What is the interest rate of each investment?

Answer 1

18,000(p + 0.006) - 5000p = 1148

18,000p + 108 - 5000p = 1148

13,000p = 1040

p = 0.08 = 8%

 

0.08 + 0.006 = 0.86 = 8.6%

Answer 2

(R+0.006)*18000-R*5000=1148

 

13000R+ 108=1148

13000R=1040

R=1040/13000