John had a stock of 1200 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? Answers.
A) 50.4%
B) 23.8%
C) 66.5%
D) 34.9%
E) 43.5%
Let N be the total number of books sold. Hence   N = 75 + 50 + 64 + 78 + 135= 
<gadget id="calculator">75 + 50 + 64 + 78 + 135</gadget>
<output>402</output>
402   Let M be the books NOT sold   M= 1200 - N = 1200 - 402= 
<gadget id="calculator">1200 - 402</gadget>
<output>798</output>
798   Percentage   Books not sold / total number of books= 798/1200= 
<gadget id="calculator">798/1200</gadget>
<output>133/200 = around 0.665</output>
0.665= 66.5%   correct answer 66.5%
<result>C</result>
John had a stock of 1200 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?