a dishonest shopkeeper professes to sell pulses at the cost price , but he uses a false weight of 980 gm . for a kg . his gain is … % .
"his percentage gain is 100 * 20 / 980 as he is gaining 20 units for his purchase of 980 units . so 2.04 % . . answer : a"
multiply(subtract(inverse(divide(980, multiply(multiply(add(const_4, const_1), const_2), const_100))), const_1), const_100)