Re: A research study found that, of 500 people surveyed, 220

let x = only A =120 given
y = both A and B
z=only B
w= neither A and B = 220 given
also given z=3*y

from below picture
x+y+z+w = 500
using above given values
y+z =160

and 4*y = 160(since z=3*y)
y=40

Sol:A