SOLUTION: Problem Page Tony invested his savings in two investment funds. The amount he invested in Fund A was $5000 less than the amount he invested in Fund B. Fund A returned a 6% profit

Let x = the amount invested in fund A at 6%  and

let y = the amount invested in fund B at 7%.


Then your first equation is

    y - x = 5000.                              (1)


Fund A returned  0.06*x dollars;  fund B returned 0.07*y dollars.


So, you second equation is


    interest + interest = total interest,    or


    0.06x    + 0.07y    = 2300     dollars     (2)   


From equation (1) express y = 5000+x  and substitute it into equation (2), replacing y:


    0.06x + 0.07*(5000+x) = 2300.


Sinplify and solve for x:


    0.06x + 350 + 0.07x = 2300


    0.13x = 2300 - 350 = 1950  ====>  x =  = 15000.


Answer.  The amount invested in fund A is  $15000;  the amount invested in fund B  is 5000 more, i.e.  $20000.


Check.  0.06*15000 + 0.07*20000 = 2300 dollars.   ! Correct !