Question 678245
If x is the amount she invested at 5%, than 5x (5 times x) is the amount she invested at 8%.

{{{x*(5/100)}}} is what she earns from the 5% investment, and {{{5x*(8/100)}}} is what she earns from the 8% investment. Thus you can write:

{{{x*(5/100) + 5x*(8/100) = 3150}}}

{{{x/20 + 8x/20 =3150}}}

{{{9x/20 = 3150}}}

{{{x = 3150*20/9}}}

{{{x = 7000}}}

Thus the woman invested $7,000 at 5% and $35,000 at 8%.