Question

Nico is saving money for his college education He invest some money at 6% and 1300 less than that amount ay 3%. The investments produced a total of 150 intrest in 1year. How much did he invest at each rate

Answer 1

2100 at 6% and 800 at 3%

Explanation:

Let's call the amount of money Nico invests at 6% X, so the amount he invests at 3% will be (X-1300).

if the total interest produced is 150 in one year, we can formulate the following equation:

0.06*X + 0.03*(X-1300) = 150

0.06*X + 0.03*X - 39 = 150

0.09*X = 189

X = 189/0.09 = 2100

The second investment is X - 1300 = 800

Nico invested 2100 at 6% and 800 at 3%

Answer 2

At 6%, $2,100 invested, at 3%, $800 invested

Explanation:

In this question, we are asked to calculate the amount of money which was invested at two different rates given the interest accursed at both rates.

Since we do not know the amount of money invested, we can say let the amount of money invested be x.

Now, generally the formula for simple interest stands at;

I = PRT/100, with our time being 1 year, there is no difference with just multiplying the principal by the rate.

At 6%, he invested $x.

Mathematically the interest here would be;

6/100 * x = 6x/100

At 3%, amount invested is 1300 less than x, meaning x-1300

Interest here is 3/100 * (x-1300)

Adding both interests will give a total of 150.

Hence;

6x/100 + 3(x-1300)/100 = 150

Let’s now solve for x

(6x + 3x -3900)/100 = 150

9x -3900 = 15000

9x = 15000 + 3900

9x = 18,900

x = 18,900/9

x = $2,100

At 6%, $2,100 invested, at 3%, $800 invested