If three 6 volt batteries are connected in parallel, what will be the resultant voltage?

When batteries are connected in parallel, the voltage across the terminals remains the same as that of a single battery, while the capacity (or total current supply) increases. In this case, since all three batteries are 6 volts, connecting them in parallel will maintain the voltage at 6 volts. The current capacity increases because the batteries can supply more current together than each could alone, but the voltage does not add up as it would in a series connection. Therefore, the resultant voltage when three 6 volt batteries are connected in parallel is indeed 6 volts.