Question

    A student multiplied a number by 4/5 instead of 5/4. What is the percentage error in the calculation?

    A 27% Correct Answer Incorrect Answer
    B 64% Correct Answer Incorrect Answer
    C 36% Correct Answer Incorrect Answer
    D 24% Correct Answer Incorrect Answer

    Solution

    Let the required number = (LCM of denominator 4 and 5) = 20 According to the question, Wrong answer = 4/5 times; 20 = 16 Correct answer = 5/4 times; 20 = 25 Required percentage of error = [(25-16)/ 25] times; 100 = 36%

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