Question

A man invests x amount of money at 2% interest. The next day he invests $800 more than the previous morning into an account that earns 4% interest. At the end of one year he has earned a total of $112 in interest. How much money was invested in each account?



Which of the following equations could be used to solve the problem?

0.02x + 0.04(800) = 112
0.02x + 0.04(x + 800) = 112
0.04x + 0.02(x + 800) = 112
0.04x - 0.04(x + 800) = 112

Answer 1

Let's rewrite our 2% as a decimal, \(\large 0.02\).
Our amount invested is represented by \(\large x\).

The interest based off of the initial investment can be calculated by multiplying our `amount` by our `interest rate`.
\(\large 0.02x\)

Understand how we came up with that part of the problem?

Answer 2

The next day, our amount has increased by $800.
It's the same amount \(\large x\), but increased by 800.
We can write it like this \(\large (x+800)\).

And this amount is invested at 4%, or as a decimalm \(\large 0.04\)

Do you think you can figure out how the second part should look, based on what we did for the first day?

Answer 3

That's so confusing you could put it in latin and i would understand it better. Just tell me what the anwser is? lol