A pupil multiplied a figure by $\frac{3}{5}$ rather than $\frac{5}{3}$. What is the percentage error in the calculation?

64

Let number is = 15x

Wrongly multiplied by \(\frac{3}{5}\) . So , number we get =

= \(\frac{3}{5}\) × 15x = 9x

In actual it should be multiplied by \(\frac{5}{3}\) . So , desired number =

= \(\frac{5}{3}\) × 15x = 25x

Difference = 25x - 9x = 16x

Percentage error = \(\frac{16x}{25x}\)  × 100 = 64%