To set up the inequality in standard form, we start by noting the costs of the writing instruments and the maximum amount Sophia can spend.
Let:
- \( x \) = the number of mechanical pencils (costing $1 each)
- \( y \) = the number of pens (costing $2 each)
The total cost for the mechanical pencils is \( 1x \) (since each mechanical pencil costs $1) and the total cost for the pens is \( 2y \) (since each pen costs $2).
Since Sophia can spend up to $15, we write the inequality that represents this situation:
\[ 1x + 2y \leq 15 \]
To express this in standard form, we rearrange the inequality as follows:
\[ x + 2y \leq 15 \]
Thus, the inequality in standard form that describes Sophia's spending on mechanical pencils and pens is:
\[ x + 2y \leq 15 \]