SOLUTION: Please help me!The problem is: An investment of $1500 paid interest of $45 during a certain period. How much interest would an investment of $2000 invested at the same rate for th

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Question 130551This question is from textbook algebra
: Please help me!The problem is:
An investment of $1500 paid interest of $45 during a certain period. How much interest would an investment of $2000 invested at the same rate for the same length of time pay?
Please and Thank you=)
 This question is from textbook algebra

Found 2 solutions by checkley71, bucky:
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
45/1500=X/2,000
1,500X=45*2,000
1,500X=90,000
X=90,000/1,500
X=$60 IS THE INTEREST PAYED ON THE $2000 INVESTMENT @ THE SAME RATE.

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
Since the interest rate does not change and the period of investment remains unchanged, you
can do this problem by setting up a proportion:
.
interest (I) is to invested principal (P) as interest (I) is to invested principal (P)
.
Which in equation form becomes:
.
I%5B1%5D%2FP%5B1%5D+=+I%5B2%5D%2FP%5B2%5D
.
On the left side of this equation we can substitute information from the problem. The first
amount of interest is $45 and the principal invested is $1500. Substituting these values results
in:
.
45%2F1500+=+I%5B2%5D%2FP%5B2%5D
.
On the right side of the equation we know that the new principal is $2000. So we can substitute
that amount to get the equation:
.
45%2F1500+=+I%5B2%5D%2F2000
.
Proportions of this form can be solved by first doing cross multiplication. Multiply the
each numerator by the denominator on the other side and set the two products equal.
.
So in this problem multiply the numerator 45 by the denominator on the other side %282000%29
and you get %2845%2A2000%29. Then multiply the numerator I%5B2%5D by the denominator on the other
side %281500%29 and you get 1500%2AI%5B2%5D. Set the two products equal and you have the
equation:
.
1500%2AI%5B2%5D=+45%2A2000
.
Solve for I%5B2%5D by dividing both sides by 1500 and the equation becomes:
.
I%5B2%5D+=+%2845%2A2000%29%2F1500
.
Do the multiplication and division on the right side and you get the answer:
.
I%5B2%5D+=+60
.
This tells you that at the same rate of interest and for the same period if $1500 earns $45,
then an investment of $2000 will earn $60.
.
Hope this helps you to understand the problem.
.