Look at the results of a titration experiment:
| Titration 1 (rough) | Titration 2 | Titration 3 | Titration 4 | |
|---|---|---|---|---|
| Volume of acid used (cm3\text{cm}^3cm3) | 16.90 | 16.25 | 16.15 | 16.50 |
What is the accurate average volume of acid used in the titration?
16.20 cm316.20\text{ cm}^316.20 cm3
16.30 cm316.30\text{ cm}^316.30 cm3
16.45 cm316.45\text{ cm}^316.45 cm3
16.50 cm316.50\text{ cm}^316.50 cm3