Question

Una mujer invierte un total de $20,000 en dos cuotas una paga 5% y la otra y la otra paga 8% de interes simple anual si recibe $1,180.00 cuanto invirtio a cada tasa

Answer 1

For the 5% interest rate

she invested $14,000

For the 8% interest rate,

she invested $6,000

Explanation:

Here, we want to know the amount the woman invested at each rate

Let the amounts at each rates be $x and $y respectively

She invested a total of $20,000

Thus;

x + y = 20,000 •••••••••(i)

let’s calculate interest on both investments

mathematically, the formula to use is;

I = PRT/100

for the $x investment, we have

I = x * 5 * 1/100 = 5x/100 = x/20

for the $y investment, we have

i = 8 * y * 1/100 = 8y/100 = 2y/25

adding both interests equal 1,180

x/20 + 2y/25 = 1,180

Multiply through by 100

5x + 8y = 118000 ••••••(ii)

we now solve both simultaneously

from i

x = 20,000-y

Put this into ii

5(20,000-y) + 8y = 118000

100,000 -5y + 8y = 118000

3y = 118000-100000

3y = 18,000

y = 18,000/3

y = $6,000

From i we know that

x = 20,000-y

x =

20,000 - 6000 = $14,000