john had a stock of 1100 books in his bookshop . he sold 75 on monday , 50 on tuesday , 64 on wednesday , 78 on thursday and 135 on friday . what percentage of the books were not sold ?
"let n be the total number of books sold . hence n = 75 + 50 + 64 + 78 + 135 = 402 let m be the books not sold m = 1100 - n = 1100 - 402 = 698 percentage books not sold / total number of books = 698 / 1100 = 0.634 = 63.4 % correct answer b"
multiply(divide(subtract(1100, add(add(add(75, 50), add(64, 78)), 135)), 1100), const_100)