<h2><em><u>Solution</u></em> : </h2>
let the last number be x
we know,
So,
therefore, the last number is 10.
The answer is 54,550 more.
Interest is $1,320. <span><span>P is the principal amount, $6,600.
</span><span>r is the interest rate, 4% per year, or in decimal form, 4/100=0.04.
</span><span>t is the time involved, 5 years time periods.
</span><span>So, t is 5 year time periods.
</span></span>I= p x r x t
In order to get the final number just add $1,320 + $6,600 which is $7,920
The answer can be readily calculated using a single variable, x:
Let x = the amount being invested at an annual rate of 10%
Let (8000 - x) = the amount being invested at an annual rate of 12%
The problem is then stated as:
(x * 0.10) + ((8000 - x) * 0.12) = 900
0.10(x) + ((8000 * 0.12) - 0.12(x)) = 900
0.10(x) + 960 - 0.12(x) = 900
0.10(x) - 0.12(x) = 900 - 960
-0.02(x) = -60
-0.02(x) * -100/2 = -60 * -100/2
x = 6000 / 2
x = 3000
Thus, $3,000 is invested at 10% = $300 annually; and $8,000 - $3,000 = $5,000 invested at 12% = $600 annually, which sum to $900 annual investment.
