A student multiplied a number by 2/5 instead of 5/2. What is the percentage error in the calculation?
Let the required number = (LCM of denominator 2 and 5) = 10 According to the question, Wrong answer = 2/5 × 10 = 4 Correct answer = 5/2 × 10 = 25 Required percentage of error = (25-4)/25 × 100 = 84%
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