a person invested $6500 for 1 year, part at 7%, part at 10%, and the remainder at 14%.

Question

the total annual income from these investments was $758. the amount of money invested at 14% was 700 more than invested at 7% and 10% combined. Find the amount invested at each rate

Answer 1

a + b + c = 6500

0.14a + 0.07b + 0.1c = 758

a = b + c + 700

 

a = -b - c + 6500

a = b + c + 700

2a = 7200

a = 3600

 

b + c = 3600 - 700

b + c = 2900

 

0.14(3600) + 0.07b + 0.1c = 758

504 + 0.07b + 0.1c = 758

0.07b + 0.1c = 254

 

-0.07(b + c) = -0.07(2900)

 

-0.07b - 0.07c = -203

0.07b + 0.1c = 254

              0.03c = 51

                     c = 1700

 

b = 6500 - (1700 + 3600)

b = 6500 - 5300

b = 1200