Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. A survey of $500$ television viewers produced the following information, $285$ watch football, $195$ watch hockey, $115$ watch basket-ball, $45$ watch football and basket ball, $70$ watch football and hockey, $50$ watch hockey and basket ball, $50$ do not watch any of the three games. The number of viewers, who watch exactly one of the three games are

Sets

Solution:

image
$a+e+f+g=285, \quad b+d+f+g=195$
$c+d+e+g=115, \quad e+g=45, f+g=70, d+g=50$
$a+b+c+d+e+f+g=500-50=450$
So $, a+f=240, b+d=125, c+e=65$
$a+e=215, b+f=145 ; b+c+d=165$
$a+c+e=255 ; a+b+f=335$
Solving we get
$b =95, c =40, a =190, d =30, e =25, f =50$
and $g =20$
Desired quantity $= a + b + c =325$