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A student multiplied a number by 4/7 instead of 7/4. What is the percentage error in the calculation?
- A206.25 percent
- B67.35 percent
- C33.67 percent
- D103.13 percent
Answer not set
Discussion 1
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CCommunity
Let the number to be multiplied be x.
The actual answer is 7x/4
The answer due to error is 4x/7
Hence, error = (7x/4) − (4x/7) = (49x − 16x)/28
Error = 33x/28
Error percentage = (Error/Actual answer) × 100 = [(33x/28)/(7x/4)] × 100
Error % = 33 × 100/49 = 67.35%
The actual answer is 7x/4
The answer due to error is 4x/7
Hence, error = (7x/4) − (4x/7) = (49x − 16x)/28
Error = 33x/28
Error percentage = (Error/Actual answer) × 100 = [(33x/28)/(7x/4)] × 100
Error % = 33 × 100/49 = 67.35%