d jeans. 4 shirts and 2 pairs of jeans [tex]$\left\{\begin{array}{l}4s + 2j = 64 \\ 3s + 3j = 72\end{array}\right.$[/tex] How much do one shirt and one pair of jeans cost?



Answer :

Let's solve the system of linear equations given by:

[tex]\[ \begin{cases} 4s + 2j = 64 \\ 3s + 3j = 72 \end{cases} \][/tex]

Where [tex]\( s \)[/tex] represents the price of one shirt and [tex]\( j \)[/tex] represents the price of one pair of jeans.

### Step 1: Simplify the equations if possible.
The second equation is:

[tex]\[ 3s + 3j = 72 \][/tex]

We can divide the entire equation by 3 to simplify it:

[tex]\[ s + j = 24 \][/tex]

Now, we have:

[tex]\[ \begin{cases} 4s + 2j = 64 \\ s + j = 24 \end{cases} \][/tex]

### Step 2: Solve the simpler system of equations.
From the simplified second equation:

[tex]\[ s + j = 24 \][/tex]

we can express [tex]\( j \)[/tex] in terms of [tex]\( s \)[/tex]:

[tex]\[ j = 24 - s \][/tex]

### Step 3: Substitute the expression from Step 2 into the first equation.
Substitute [tex]\( j = 24 - s \)[/tex] into the first equation:

[tex]\[ 4s + 2(24 - s) = 64 \][/tex]

### Step 4: Solve for [tex]\( s \)[/tex].
Expand and simplify the equation:

[tex]\[ 4s + 48 - 2s = 64 \][/tex]

Combine like terms:

[tex]\[ 2s + 48 = 64 \][/tex]

Subtract 48 from both sides:

[tex]\[ 2s = 16 \][/tex]

Divide by 2:

[tex]\[ s = 8 \][/tex]

So, the price of one shirt is [tex]\( s = 8 \)[/tex].

### Step 5: Solve for [tex]\( j \)[/tex] using the value of [tex]\( s \)[/tex].
Substitute [tex]\( s = 8 \)[/tex] back into the simplified second equation [tex]\( s + j = 24 \)[/tex]:

[tex]\[ 8 + j = 24 \][/tex]

Subtract 8 from both sides:

[tex]\[ j = 16 \][/tex]

So, the price of one pair of jeans is [tex]\( j = 16 \)[/tex].

### Final solution:
- The price of one shirt is [tex]\( 8 \)[/tex] units.
- The price of one pair of jeans is [tex]\( 16 \)[/tex] units.

Therefore, one shirt costs 8 units and one pair of jeans costs 16 units.