n(A) = 40% of 10,000 = 4,000
n(B) = 20% of 10,000 = 2,000
n(C) = 10% of 10,000 = 1,000
n (A

B) = 5% of 10,000 = 500
n (B

C) = 3% of 10,000 = 300
n(C

A) = 4% of 10,000 = 400,
n(A

B

C) = 2% of 10,000 = 200
We want to find n(A only) = n(A) – [n(A

B) + n(A

C)] + n(A

B

C)=
n(A only) = 4000 – [500 + 400] + 200 = 4000 – 700 = 3300
Similarly, n(B only) = n(B) – [n(A

B) + n(B

C)] + n(A

B

C)
n(B only) = 2000 - [500+300]+200 = 1400
n(none of A, B and C) = 10,000 - [n(A)+n(B) + n(C) - n (A

B) - n(B

C) - n (C

A) + n(A

B

C)]
n(none of A, B and C) = 10,000 - [4000+2000+1000 - 500-300-400 + 200]
n(none of A, B and C) = 4000