Answer :
Answer:
d. 24,000 at 3% and 8,000 at 5.5%
Step-by-step explanation:
Let the principal for the 3% loan be [tex]P_a[/tex] and that for the 5.5% loan be [tex]P_b[/tex]. Let their respective interests be [tex]I_a[/tex] and [tex]I_b[/tex].
Then
[tex]I_a=P_a\times3\%\times4=0.12P_a[/tex]
[tex]I_b=P_b\times5.5\%\times4=0.22P_b[/tex]
From the question, the sum of the interests is 4640.
[tex]I_a + I_b = 4640[/tex]
[tex]0.12P_a + 0.22P_b = 4640[/tex]
Also, the total amount borrowed is 32000.
[tex]P_a + P_b = 32000[/tex]
To solve the last two equations simultaneously, multiply the second by 0.12 and subtract from the first (this eliminates [tex]P_a[/tex]).
[tex]0.10P_b = 800[/tex]
[tex]P_b = 8000[/tex]
From [tex]P_a + P_b = 32000[/tex],
[tex]P_a = 32000 - P_b = 32000-8000 = 24000[/tex]
Hence, $24,000 was borrowed at 3% and $8,000 was borrowed at 5.5%.