Answer:
He invested 3,000 at 7% and 4,000 at 9%.
Step-by-step explanation:
From the information given, you can write the following equations:
x+y=7,000 (1)
0.07x+0.09y=570 (2)
You can solve for x in (1)
x=7,000-y (3)
Now, you can replace (3) in (1) and solve for "y":
0.07(7,000-y)+0.09y=570
490-0.07y+0.09y=570
0.02y=80
y=80/0.02
y=4,000
Finally, you can replace the value of "y" in (3):
x=7,000-4,000
x=3,000
According to this, the answer is that he invested 3,000 at 7% and 4,000 at 9%.
