Answer:
66.67%
Explanation:
They do not say that I estimate a value of 350 chips but in reality there were 210 chips in total, we have that the error formula is:
Percentage error (%) = (estimated value - actual value) / actual value × 100 (in absolute value)
replacing:
Percentage error (%) = | 350 - 210 | / 210 × 100
Percentage error (%) = 140/210 * 100
Percentage error (%) = 66.67
Which means that the percentage error is 66.67%