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