Question Number 174661 by Mastermind last updated on 07/Aug/22
$$\mathrm{After}\:\mathrm{being}\:\mathrm{marked}\:\mathrm{down}\:\mathrm{20}\:\mathrm{percent}. \\ $$$$\mathrm{a}\:\mathrm{calculator}\:\mathrm{sells}\:\mathrm{for}\:\$\mathrm{10}.\:\mathrm{The}\:\mathrm{Original} \\ $$$$\mathrm{selling}\:\mathrm{price}\:\mathrm{was}\:? \\ $$
Answered by Rasheed.Sindhi last updated on 07/Aug/22
$${Let}\:{original}\:{selling}\:{price}={p} \\ $$$${Discounted}\:{price}: \\ $$$${p}−\left(\mathrm{20\%}\:{of}\:{p}\right)=\$\mathrm{10} \\ $$$${p}−\frac{\mathrm{20}}{\mathrm{100}}×{p}=\mathrm{10} \\ $$$${p}−\frac{\mathrm{1}}{\mathrm{5}}{p}=\mathrm{10} \\ $$$$\frac{\mathrm{4}}{\mathrm{5}}{p}=\mathrm{10} \\ $$$$\:\:\:\:\:{p}=\frac{\mathrm{10}×\mathrm{5}}{\mathrm{4}}=\$\mathrm{12}.\mathrm{50} \\ $$