Answer:
interest rate = 5.01%
Explanation:
[tex]a (1+r)^{2} + b (1+r) = c [/tex]
p0= a = 1000
p1= b = 2400
amount = c= -3623
rate = ?
Because the first amount is investment for a period of 2 years, and the second 1 year, we can solve for rate using the quadratic equation:
[tex]x = \frac{ - b +/- \sqrt{b^{2} - 4ac} }{2a}[/tex]
[tex]1000 (1+r)^{2} + 2400 (1+r) = 3623[/tex]
[tex]1000 (1+r)^{2} + 2400(1+r) - 3,623 = 0[/tex]
A = 1000
B = 2400
C = -3623
[tex]x = \frac{ - 2400 \sqrt{2400^{2} - 4*1000*-3623} }{2*1000}[/tex]
x1 = 1.0501111083677623
x2 = -3.4501111083677625
We use the positive root:
x1 = 1.0501111083677623 = (1+r)
1.0501111083677623 - 1 = r = 0.0501111 = 5.01%
EDIT several problems with the math tool but kind of worked