Bobby wants to invest $100. His brother invested $2,000 for one year and earned $60 in simple interest.
If Bobby invests his money for one year at the same interest rate as his brother, how much will he earn?
We can use proportions to solve this problem.
First, we need to find the interest rate that Bobby's brother earned:
$60 = 0.03 \times 2000
So the interest rate is 0.03 or 3%.
Now we can set up a proportion:
$60 is to $2,000 as X is to $100
This can be written as:
60/2000 = X/100
Simplifying, we get:
X = (60/2000) * 100 = $3
Therefore, if Bobby invests $100 for one year at the same interest rate as his brother, he will earn $3 in simple interest.