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2 votes
25 points! Please help!

I need help! You have 5 attempts and if you are wrong, I will let you know so you can make corrections and I get the right answer.

25 points! Please help! I need help! You have 5 attempts and if you are wrong, I will-example-1

1 Answer

5 votes

Obviously, if he were to only maximize his income he would put all money on the higher interest. But to reduce the risk he will balance the investment. He will put a fraction a (between 0 and 1) of the 710000 on 1% and the rest (1-a) on the 4.5%. Both interests together must then satisfy to add up to 18000.

So written as an equation:


710000\cdot a\cdot 0.01 + 710000\cdot(1-a)\cdot 0.045 = 18000

I am not going to solve step by step assuming you can solve for a (if not let me know) but the solution is


a = 279/497

So that means he should put


710000\cdot (279)/(497) \approx 398571 on the 1% account, and the rest 311429 on the riskier 4.5% account.


User Akshay
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