Answer:
Step-by-step explanation:
The formula of simple interest is:
Where I is the interest earned after t years
r is the interest rate
is the initial amount
We know that the investment was $20,000 in two accounts
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<u><em>For the first account</em></u> r = 0.07 per year.
Then the formula is:
Where
is the initial amount in account 1 at a rate
during t = 1 year
<u><em>For the second account </em></u>r = 0.05 per year.
Then the formula is:
Where
is the initial amount in account 2 at a rate
during t = 1 year
Then
We know that the final profit was I $1,280.
So
Substituting the values ,
and I we have:
As the total amount that was invested was $20,000 then
Then we multiply the second equation by -0.07 and add it to the first equation:
Then