Question 377019: I apologize if this posted twice...but I don't think the first one went through.
Jane won $10,000. She plans to invest into two accounts one paying 5% interest and the other paying 7% interest. If she invests twice as much in the 7% account as she invests in the 5% account, how much interest will she earn in one year?
I couldn't figure out a way to use rPI so I divided 10,000 by 3, multiplied 3,334 by .05 and 6,666 by .07 to get $633 interest in one year.
Is this correct? Is there a "better" way to do this?
Answer by Edwin McCravy(20060)   (Show Source):
You can put this solution on YOUR website!
Your work is correct. The only thing you could have done differently would be
to get the investments to the nearest penny instead of the nearest dollar.
Then the interest on the $3333.33 would be $166.66 (interest is always
rounded down, for doing that benefits the interest-giver and not the
investor. And over a long period of time with many investors those small
fractions of a cent amount to many thousands of dollars!) The interest on
the $6666.67 would be $466.66 and the total interest would be $633.32.
I'm not sure that's really "better". If so, it isn't much "better", as 32
cents isn't worth very much these days! :-)
Edwin
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