Math Help for Section 3.5, Page 139

Example
4: Tip
Writing the equation is an important step in solving mixture
problems. 

Verbal Model:

Recall the verbal model for solving mixture problems.

Substitute the labels from the solution of Example 4 into the
model.

Example
4: Check

    $\eqalign{ 0.15\left( {100}
\right) +
1.00\left( x \right) =& 0.32\left( {100 + x}
\right)&{\small\color{red}\quad\quad\text{Write original
equation.}}  \cr0.15\left( {100} \right) +
1.00\left( {\color{red} 25} \right) \overset{?}{=}& 0.32\left(
{100+{\color{red}25}}
\right)&{\small\color{red}\quad\quad\text{Substitute 25
for }x.}  \cr 0.15\left( {100} \right) + 1.00\left(
{25} \right)
\overset{?}{=}& 0.32\left( {125}
\right)&{\small\color{red}\quad\quad\text{Add.}}  \cr
15 + 25 \overset{?}{=}&
40&{\small\color{red}\quad\quad\text{Multiply.}}  \cr
40 =&
40&{\small\color{red}\quad\quad\text{Solution
checks. }\checkmark} } $