Question

Susan invested her savings in two investment funds. The amount she invested in Fund A was 3 times as much as theamount she invested in Fund B. Fund A returned a 8% profit and Fund B returned a 6% profit. How much did she invest inFund B, if the total profit from the two funds together was $1800?

Answer 1

In this problem we have two incognitas, so we need to have two equations to solve the problem:

the first equation is the invest amound: (A is the amount invested in fund A, and B is the amound invested in the fund B)

`A=3B`

And the second equation is going to be the total profit:

`A0.8+B0.6=1800`

Now we can replace the equation 1 in the second one:

`3B(0.8)+B0.6=1800`

And finally we solve for B:

`\begin{gathered} 2.4B+0.6B=1800 \\ B(2.4+0.6)=1800 \\ B(3)=1800 \\ B=(1800)/(3) \\ B=600 \end{gathered}`