Story Problem for Calculus

Question

A woman invests a total of $20,000 in two accoutns, one paying 5% and the other paying 8% simple interest per year.  Her annual interest is $1180.  How much did she invest at each rate?

 

Answer 1

Say, amount invested at 5percent= x

 

So, amount invested at 8 percent = (20000-x)

 

Total interest amount =

 

x*.05*1 + (20000-x)*.08*1 = 1180

 

5x + 160000- 8x = 118000

 

-3x =-42000

 

 x= 14000

Amount at 5percent=14000

Amount at 8percent = 6000