A student multiplied a number by \(\frac{3}{5}\) instead of \(\frac{5}{3}.\) What is the percentage error in the calculation?
Answer: D
Let the number be \(x.\)
Then, error \(= \frac{5}{3}x - \frac{3}{5}x = \frac{16}{15}x.\)
Error % \(= (\frac{16x}{15} \times \frac{3}{5x} \times 100)\)% \(= 64\)%