Answer
100lb; 50lb; 0.0357; 3.57%
Work Step by Step
For the measurement 1400 lb, we have:
The precision is $100$ because the last non-zero digit $4$ is in the $100$ place.
The greatest possible error is one-half the precision:
$0.5\cdot 100=50\ lb$
The relative error is:
$relative~error=\dfrac{greatest~possible~error}{measurement}$
$\frac{50 \ lb}{1400\ lb}=0.0357$ the percent of error is $3.57\%$.
