JEE Main · 2019 · 09 Apr 2019 · Shift 2 · Probability

Two newspaper A and B are published in a city. It is known that

25%

of the city populations reads A and

20%

reads B while

8%

reads both A and B. Further,

30%

of those who read A but not B look into advertisements and

40%

of those who read B but not A also look into advertisements, while 50% of those who read both A and B look into advertisements. Then the percentage of the population who look into advertisement is:

(A)12.8
(B)13.5
(C)13.9✓ Correct
(D)13

Answer: (C)

Solution

Work with a population of

100

. Readers of A number

25

, of B number

20

, and

8

read both, so

17

read only A and

12

read only B. The advertisement-watchers are

30%

of the A-only group,

40%

of the B-only group and

50%

of the both group:

0.30 \times 17 + 0.40 \times 12 + 0.50 \times 8 = 5.1 + 4.8 + 4.0 = 13.9

. So

13.9%

of the population looks into advertisements.

JEE Main · 2019 · 09 Apr 2019 · Shift 2 · Single correct option

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JEE Main · 2019 · 09 Apr 2019 · Shift 2 · Probability

Solution

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