1. **Problem statement:** A vacuum gauge connected to a tank reads 30 kPa at a location where the barometric reading is 755 mm Hg. Determine the absolute pressure in the tank. 2. **Relevant formula:** Absolute pressure is given by $$P_{abs} = -P_{vac} + P_{atm}$$ where $P_{vac}$ is the vacuum gauge pressure (positive value) and $P_{atm}$ is the atmospheric pressure. 3. **Convert barometric reading to atmospheric pressure:** Given barometric pressure = 755 mm Hg. We know 760 mm Hg = 101.325 kPa. So, $$P_{atm} = \frac{755}{760} \times 101.325 = 100.58\, kPa$$ 4. **Calculate absolute pressure:** Given vacuum gauge pressure $P_{vac} = 30$ kPa, $$P_{abs} = -30 + 100.58 = 70.58\, kPa$$ 5. **Interpretation:** The absolute pressure in the tank is 70.58 kPa, which is less than atmospheric pressure due to the vacuum. **Final answer:** $$\boxed{70.58\, kPa}$$