The probability that the first critic favours the book is P(A)=
2
2+5
=
2
7
∴P(A′)=1−
2
7
=
5
7
The probability that the second critic favours the book is P(B)=
3
3+4
=
3
7
∴P(B′)=1−
3
7
=
4
7
The probability that the third critic favours the book is P(C)=
4
4+3
=
4
7
∴P(C′)=1−
4
7
=
3
7
∴ Majority will be in favour of the book if at least two critics favour the book. Hence, the probability is P(A∩B∩C′)+P(A∩B′∩C) +P(A′∩B∩C)+P(A∩B∩C) =P(A)⋅P(B)⋅P(C′)+P(A)⋅P(B′)⋅P(C) +P(A′)⋅P(B)⋅P(C)+P(A)⋅P(B)⋅P(C)