An accountant divides the total by 7 instead of multiplying by 9. What is the…

Solution: step-by-step

• Let the original number be x. The correct operation (multiply by 9) gives the true value 9x.

• The accountant instead divides by 7, giving the obtained value x/7.

• Percentage error = (obtained − true) / true × 100% = (x/7 − 9x) / (9x) × 100%.

• Compute the fraction: (1/7 − 9) / 9 = (1 − 63) / 63 = −62/63.

• Thus percentage error = (−62/63) × 100% ≈ −98.4127%.

Answer: 98.41% (approximately).

Note: The negative sign indicates the accountant's value is smaller than the correct value; the magnitude of the error is 98.41%.