If a man wants to invest 10000 dollars at 6 percent and 7 percent but wants to make two times as much at the 7 percent rate how much should he invest at each rate?
If the man invest x dollars at a 6% rate, he will invest 1,000 - x dollars at a 7% rate. So the equation will be:
2(0.06x) = 0.07(1,000 - x)
0.12x = 70 - 0.07x add 0.07x to both sides;
0.19x = 70 divide by 0.19 to both sides;
x = 368.42
Thus, the man will invest $ 368.42 at a rate 6%, and $ 631.58 at a rate 7%.
So he will make (368.42 x 0.06) $ 22.11 in the first investment, and (631.58 x 0.07) $44.21 in the second investment.