Chapter 6, Problem 30SGR

To determine

An equation that models the given problem . How much money did Jonathan have in his account at the beginning of the month .

Answer to Problem 30SGR

  $\text{about \$91}\text{.33}$

Explanation of Solution

Given Information:

During the last month, Jonathan has made two deposits of $45 , made a deposit of double his original balance,and has withdrawn $35 five times.His balance is now $189.

Calculation:

  $\begin{array}{l}\text{Let }\\ Balance\text{ in Jonathan's account in the beginning of the month = x}\\ \text{Deposit made by Jonathan = (2}\times \text{45)}+2x\\ \text{Withdrawn made by Jonathan = }5\times 35\\ \text{Balance now in Jonathan's account =189= }x+(2\times 45)+2x-(5\times 35)\\ Solve\text{ the equation for 'x':}\\ x+90+2x-175=189\\ 3x-85=189\\ 3x=189+\mathrm{85...........}[\text{add 85 each side]}\\ 3x=274\\ \frac{3x}{3}=\frac{274}{3}\mathrm{...............}[\text{divide each side by 3]}\\ x\approx 91.33\\ \text{The original balance in the account in the beginning of}\\ \text{the month was about \$91}\text{.33}\end{array}$