Question 931585
Let x = amount invested at 9%
    y = amount invested at 6%

mrs. Rosario invested part of Php35,000 in a bank paying 9% interest for 2 years and the balance in another bank paying 6% interest for 4 years.
x+y=35000
x=35000-y
It turns out that the two investments earned equal interest.
I=Prt
(.09)(2)(x)=(.06)(4)(y)
       .18x=.24y
.18(3500-y)=.24y
  6300-.18y=.24y
       6300=.42y
      15000=y
      20000=x

Mrs. Rosario invested Php20000 at 9% and Php15000 at 6%.