Answer
a. 100 V
b. 50 V
Work Step by Step
For the measurement $2300~V$, we have
a. The precision is $100 V$ (because the last non-zero digit $3$ is in the $100$ place).
b. The greatest possible error is one-half the precision:
$$0.5\cdot 100 \ V= 50 \ V.$$
