Question 767176
Let's call the part he invested for 6% x. Then the other part will be 34000-x. Now, 6% of x plus 4% of 34000-x has to be 1540, or {{{6x/100+(4(34000-x))/100=1540}}}. So {{{6x+136000-4x=154000}}}, or {{{2x=18000}}}. So he invested 9000 dollars for 6% and 25000 dollars for 4%.

We can check, and it indeed holds: {{{0.06*9000+0.04*25000=540+1000=1540}}}