Answer:
Absolute error = 1.3 kg
Percent error = 10.56 %
Step-by-step explanation:
Real weight of the mountain bike = 12.3 kg.
Weight of mountain bike estimated by Lucy  = 11 kg .
Now,
Error in the weight estimated = Actual weight of the bike - Estimated  Â
                                         weight of bike by Lucy .
                        = 12.3 - 11 kg
                        = 1.3 kg.
Thus , Absolute Error in estimation = Â 1.3 kg.
Now,
Percent error in the estimation of weight = [tex]\frac{Absolute error }{Real weight }[/tex]×100
                                  = 10.56%
So , Percent error in the measurement = 10.56 %