Elementary Algebra

$10d+5n+p$
We multiply $10$ by $d$ because each dime is worth $10$ cents; we multiply $5$ by $n$ because each nickel is worth $5$ cents; and we multiply $1$ by $p$ because each penny is worth $1$ cent. We then must add these three numbers to get the total number of cents that she has in her bank. This gives us $10d+5n+1p$, which is equal to $10d+5n+p$.