Question

A shopkeeper marks an article with

Answer 1

$let \: cp \: be \: 100 \\ then \: mp \: be \: 140 \\then \\ \: \: \\ sp \: be \: 140 - 140 (20 \div 100) = 140 - 28 = 112 \\ here \: gain \: = 112 - 100 = 12 \\ hence \: gain \: \% = 12 \\ hope \: this \: will \: help \: u$