word problems

Question

Joe invest $4000. Part is invested at 10% and part at 12%. If he made a total of $460 on the interest, how much did he invest at each rate

 

Answer 1

If we assume simple interest for 1 year, then we let x = amount invested at 10% and 4000-x = amount invested at 12%

 

460 = .1x + .12(4000-x)

 

460 = .1x + 480 - .12x

 

-20 = -.02x

 

x = 1000 at 10%, 3000 at 12%