Question

Last year Marta invested money in two accounts. The first account had an interest rate of 4% and the second account had an interest rate of 3%. If she invested $300 more in the first account than the second and her total interest income was $425, how much did she invest at each rate?

Answer 1

Let principal of second acc =X

principal of first =X+300

Total Interest Received=Interest received in through acc 1 + Interest received through acc 2

425=P×R×T/100 +P×R×T/100

425=[(X+300)×4×1)/100 + X×3×1/100]

425=(4X+1200+3x)/100

42500=7X+1200

X=5900

First acc=X+300=5900+300=6200

Secnd acc=5900

Answer 2

$\huge\boxed\bf \huge\mathfrak{answer}$

RS. 6200 AND RS. 5900

$\huge \red{STEP-BY-STEP} \\ \huge \red{ VERIFICATION:}$

LET, x+300 AND x BE THE FIRST AND SECOND INVESTMENT RESPECTIVELY.

THEN,

FOR FIRST INTEREST(I¹)

$= 4\% \: of \: (300 + x) \\ = 12 + 0.04x$

FOR SECOND INTEREST(I²)

$= 3\% \: of \: (x) \\ = 0.03x$

THEN,

TOTAL INTEREST(I)=I¹+I²

OR,

$425 = 12 + 0.04x + 0.03x$

OR,

$413 = 0.08x$

•°•

$x = 5900$

AGAIN,

x+300=6200

SO, THE INVESTMENTS OF 4% INTEREST AND 3% INTEREST ARE RS. 6200 AND RS. 5900 RESPECTIVELY.