Chapter 3.4, Problem 3GP

To determine

To Find: Investment of G in three different accounts.

Answer to Problem 3GP

$ $18000$ ,$ $6000$ and$ $26,000$

Explanation of Solution

Given Total amount Ms. G invested is $ $50,000$ .

She invested three as much money in an account that paid $8\%$ interest than an account that paid $10\%$ .

Third account earned $12\%$ interest and total interest earned in a year is$ $5160$ .

Calculation:

Let xbe the amount invested in an account which paid $10\%$ interest then amount invested in an account which paid $8\%$ is $3x$ .

Total amount invested in third account which paid $12\%$ is.

  $\begin{array}{l}=50,000-\left(x+3x\right)\\ =50,000-4x\end{array}$

Equation for interest earned is.

  $\begin{array}{l}\text{Interest}=\text{Amount}\times \text{Rate}\times \text{Time}\\ 3x\times \frac{8}{100}\times 1+x\frac{10}{100}\times 1+\left(50000-4x\right)\times \frac{12}{100}\times 1=5160\\ 3x\times 0.08\times 1+x\times 0.10\times 1+\left(50000-4x\right)\times 0.12\times 1=5160\\ 0.24x+0.10x+6000-0.48x=5160\\ 0.14x=5160\\ x=6000\end{array}$

Amount invested in an account which paid $8\%$ is.

  $\begin{array}{l}=3x\\ =3\times 6000\\ =18000\end{array}$

Total amount invested in third account which paid $12\%$ is.

  $\begin{array}{l}=50,000-4x\\ =50,000-4\times 6000\\ =26,000\end{array}$ .

Therefore, amount invested in first which paid $8\%$ is $18000$ , second which paid $10\%$ is $6000$ .and third account which paid

  $12\%$ is $26,000$ .