I'll give 10 points to whoever solves this problem?

Question

In planning her retirement, Carrie deposits some money at 2.5 % interest, with twice as much at 3% .Find the amount deposited at each rate if the total annual interest income is $850.

BTW the answer is $10,000 @ 2.5 % and $20,000 @ 3%

Answer 1

$10,000 @ 2.5 % and $20,000 @ 3%

:P

Answer 2

2.5x + 3y = 85000

y = 2x

therefore

2.5x + 6x = 85000

8.5x = 85000

x = 85000/8.5 = 10 000

y = 2x = 2 x 10 000 = 20 000

therefore 10 000 @ 2.5 % and 20 000 @ 3 %

Answer 3

According the condition she deposits $x at 2.5% interest and $2x at 3.0% interest.

The total annual interest is 0.025x + 0.03*2x = 850  or 0.085x=850 x=10,000

The answer is x=10,000 @ 2.5% and 20,000 @ 3.5%