find the amount invested at each rate.

Question

George invested part of his money on a bond account with an interest rate of 6%. He invested $300 more than this amount in a savings account whose interest rate was 4%. If his annual income from both investments was the same, find the amount invested at each rate.

Answer 1

a = b + 300

0.06b = 0.04a

 

Two different methods jump out at me...

 

a = 0.06b/0.04

a = 1.5b

1.5b = b + 300

0.5b = 300

b = 600

 

Or...

 

0.06b = 0.04(b + 300)

0 06b = 0.04b + 12

0.02b = 12

b = 600

 

Either way, then...

 

a = 600 + 300

a = 900

 

$600 was invested at 6% and 900 was invested at 4%.