Answer: I = 9.0 A
Explanation: Ohm's Law is defined as the relationship between voltage and current: in a circuit, the voltage accross a conductor is directly proportional to the current.
The constant of proportionality is Resistance, whose unit is ohm (Ω).
so, Ohm's Law is
V = R.I
It is asked for the current, so, rearraging:
[tex]I=\frac{V}{R}[/tex]
When added two more batteries, the voltage of the circuit triples:
[tex]V_{final}=3V_{initial}[/tex]
Since they are directly proportional, if voltage triples, so does current:
[tex]I_{final}=3I_{initial}[/tex]
[tex]I_{final}=3(3.0)[/tex]
[tex]I_{final}=[/tex] 9.0
The new current, when driven by 3 batteries is 9.0 A.