Question

    The average wage of a group of 30 labourers is Rs. 400.

    If 4 persons receiving average wage of Rs. 320 leave the group and 2 persons receiving average wage of Rs. K join the group, then the average wage of the group increases by Rs. 45. Find the value of ‘K’.
    A 870 Correct Answer Incorrect Answer
    B 880 Correct Answer Incorrect Answer
    C 820 Correct Answer Incorrect Answer
    D 830 Correct Answer Incorrect Answer

    Solution

    Total wage of 30 labourers in the initial group = 30 × 400 = Rs. 12000 New average wage of the group = 400 + 45 = Rs. 445 New number of labourers in the group = 30 – 4 + 2 = 28 So, according to the question, 12000 – 4 × 320 + 2K = 445 × 28 Or, 12000 – 1280 + 2K = 12460 Or, 12000 + 2K = 12460 Or, 2K = 12460 – 12000 = 1740 Or, K = (1740/2) = 870

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