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Forty students watched films A, B and C over a week. Each student watched either only one film or all three. Thirteen students watched film A, sixteen students watched film B and nineteen students watched film C. How many students watched all three films?

  • (A)  0   
  • (B)  2   
  • (C)  4   
  • (D)  8   
in Numerical Ability by Loyal (5.4k points) | 273 views
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C) 4..?
0
yeah i got 4

1 Answer

+1 vote

Since students watch either 1 or all 3:

let a = students who watched only A,

b = students who watched only B,

c = students who watched only C,

n = students who watched A, B and C.

Given data implies

a + n = 16 ……….[1]

b + n = 13 ……….[2]

c + n = 19 ……….[3]

and since total strength of class is 40,

a+b+c+n = 40 ……….[4]

solving for n ( [1] + [2] + [3] – [4] )

2n = 8

=> n=4

by Active (1.7k points)
0
Can you draw diagram for it

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