Chapter 12, Problem 16STP

a)

To determine

To find : A system of linear equations as per the given conditions.

Answer to Problem 16STP

  $d+35=19.5and2d+25=23$

Explanation of Solution

Given Information :

We know that, Charge of cleaning a dress = $d$ and charge of cleaning a sweater = $S$.

Formula Used:

Conversion of word problem

Calculation :

According to given condition,

  $\begin{array}{l}d+35=19.5\mathrm{...}(1)\\ and2d+2s=23\mathrm{...}(2)\end{array}$

b)

To determine

To find : To solve the system of equations.

Answer to Problem 16STP

  $d=7.5,S=4$

Explanation of Solution

Given information :

We know that, use the system of equations in sub part as to solve.

Formula Used:

Elimination method

Calculation :

Use elimination method, multiply equation $\text{(1)}$ by $\text{2}$ and then subtract equation $\text{(2)}$ from it,

  $\begin{array}{l}2d+65=39\\ 2d+25=23\end{array}$

Gives $d=7.5$ and $S=4$

c)

To determine

To find : The charge for dry cleaning of 2 dresses and 4 sweaters.

Answer to Problem 16STP

  $31\$$

Explanation of Solution

Given information :

We know that, to use values of d and S to obtain total charge.

Formula Used:

Simple calculation

Calculation :

Charges for cleaning $2$ dress and $4$ sweaters.

  $\begin{array}{l}=2d+4s\\ =2(7.5)+4(4)\\ =15+16\\ =31\$\end{array}$