Question

In a survey of 1000 consumers , 720 liked tea,450 like coffee.what is the minimum no. that must have liked both tea and coffee.

Answer 1

let X who liked only tea
Y " " " coffee
Z " " " both
here X+Y+Z =1000
and X+Z=720 ...(I)
Z+Y =450.....(II)

A/q
we have to find Y
so from Eq I and II
X+Y+Z+Z=1170

now the value
X+ Y +Z =1000
so Z =1170 - 1000 = 170

Answer 170