john had a stock of 1000 books in his bookshop . he sold 20 on monday , 120 on tuesday , 200 on wednesday , 250 on thursday and 300 on friday . what percentage of the books were not sold ?
"let n be the total number of books sold . hence n = 20 + 120 + 200 + 250 + 300 = 890 let m be the books not sold m = 1000 - n = 1200 - 890 = 798 percentage books not sold / total number of books = 890 / 1000 = 0.89 = 89 % correct answer e"
multiply(divide(subtract(1000, add(add(add(20, 120), add(200, 250)), 300)), 1000), const_100)