Of the 45 people who plan to buy newspapers, 12 bought Q, 15 bought R, 25 bought S, 8 bought both Q and S, 7 bought both R and S, 9 bought both Q and R, the number of the people bought all the three is the same as the number of the people who bought none, and 39 people bought at least one newspaper. How many people bought exactly one newspaper?
#bought none+#bought three+#single buyers=45-12-15-25+8+7+9=17, #bought at least one=39 will make 39-8-7-9=15 bought some and (17-15)=2 is #bought none=#bought three
#single buyers=17-2-2=13
sud21 wrote:Of the 45 people who plan to buy newspapers, 12 bought Q, 15 bought R, 25 bought S, 8 bought both Q and S, 7 bought both R and S, 9 bought both Q and R, the number of the people bought all the three is the same as the number of the people who bought none, and 39 people bought at least one newspaper. How many people bought exactly one newspaper?
