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Question

Rocco borrowed a total of $7000 from two student loans. One loan charged 3% simple interest and the other charged 2.5% simple interst, both payable after graduation. If the interest he owed after two yrs was $375, determine the amount of principal for each loan?

Answer 1

i = p · r · t

 

First loan:

i = (7000 - x)(0.03)(2)

i = (7000 - x)(0.06)
i = 420 - 0.06x

 

Other loan:

i = x(0.025)(2)

i = x(0.05)

i = 0.05x

 

420 - 0.06x + 0.05x = 375        combine like terms

420 - 0.01x = 375                      subtract 420 from both sides

-0.01x = -45                               divide both sides by -0.01

x = 450

 

Check:

(7000 - 4500)(0.03)(2) + (4500)(0.025)2

(2500)(0.06) + (4500)(0.05)

150 + 225

375