Answer: 42.9%
Step-by-step explanation:
Percent error is the difference between the measured and known value, which is divided by the known value, and then multiplied by 100%.
Percent error = (Estimated number- Actual number)/Actual Number × 100.
= (60 - 42)/42 × 100
= 18/42 × 100
= 0.429 × 100
= 42.9%