Aseries circuit contains three 2 ω resistors and a 6 ω resistor. the current in each resistor is 4.0 a. what is the voltage of the battery in the circuit? 2.0 v 3.0 v 32 v 48 v

The effective resistance of several resistors in series
is the sum of their individual resistances.

In this circuit, the effective resistance is 

                (2 ohms + 2 ohms + 2 ohms + 6 ohms)  =  12 Ω .

So  12 ohms  is what the battery sees.  The battery doesn't know
whether that's a single resistor, or the sum of several.

Now, the voltage across a resistor is

                     V  =  (current) · (resistance) .

For this circuit ...

                      V  =  (4.0 A) (12 Ω)  =  48 volts .