Answer:
a) 30 people , b) C
Explanation:
for a), 40 % answered yes. so 60% answered no.
But 20 people answered yes so 20/x = 0.4 which gives, x = 20/0.4
so x = total number of people = 50
the rest answered no so 50 - 20 = y
30 people answered no
b) C is the correct chart