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    Question

    What is the total number of residents in the building?

    A 500 Correct Answer Incorrect Answer
    B 300 Correct Answer Incorrect Answer
    C 400 Correct Answer Incorrect Answer
    D 320 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the number of people who read ‘The Hindu and TOI (Only)’ be x Let the number of people who read ‘The Hindu and Economic Times (Only)’ be y. Let the number of people who read ‘TOI and Economics Times (Only)’ be z. Given that: 40 + 20 +x +y = 100 =>x+y = 40 ---- (i) 70 + 20 +x+z = 150 =>x+z = 60 ----(ii) 100 + 20 +y+z = 200 =>y+z = 80 -----(iii) Adding eq. (i), (ii) and (iii), we get 2 (x+y+z) = 180 x+y+x = 90 ----(iv) Now, subtracting (iv) by (i), we get z= 50 Now, subtracting (iv) by (ii), we get y= 30 Now, by subtracting (iv) by (iii), we get X=10 Total number of residents in the building = 40 + 70 + 100 + 10 + 50 + 30 + 20 = 320.

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