a dishonest shopkeeper professes to sell pulses at the cost price , but he uses a false weight of 970 gm . for a kg . his gain is … % .
"his percentage gain is 100 * 30 / 970 as he is gaining 30 units for his purchase of 970 units . so 3.09 % . answer : a"
multiply(subtract(inverse(divide(970, multiply(multiply(add(const_4, const_1), const_2), const_100))), const_1), const_100)