Sanity checks: -
- If Rs increases by 3% then the current through the meter rises from 50 uA to 51.43 uA when 1 mA feeds the circuit
- That's an error of 2.86%
OK I agree with part 1 of your answer. But part 2 seems all mixed up. Extract from question : -
- You didn't alter Rs in the denominator to account for it having an uncertain value.
- Putting the numbers into the formula (corrected or not) does not give 3.15% by a long way