Q.After allowing a trade discount of 15%, a trader charges ₹4,250 for an article. Find the list price.

Rearrange the net-price formula to solve for the list price $L$.

Here $N=₹4{,}250$ and $d=15\%$; the list price $L$ is unknown.

Step 1 — Rearrange the net-price formula for $L$. Since $N=L(1-d/100)$,

Step 2 — Evaluate.

$L = ₹5{,}000$ …

Multiplying the net price by $(1-d/100)$ instead of dividing by it is a common inversion here — since the list price must always be LARGER than the net price (a discount only ever reduces the price), a computed …