Quantitative problems like this one usually can't be solved
without knowing the UNITS of the given quantities.
I can ASSUME the units, and then solve the problem according to
my assumptions, but you need to keep in mind that my solution
may not be correct.
I'm going to assume that the resistance of the circuit is 18 KILO-OHMS,
and the current is 15 MILLIAMPERES. If these assumptions are correct,
then I can use the simple form of Ohm's Law:
Voltage = (current) times (resistance)
= (0.015 Amperes) times (18,000 ohms)
= 270 VOLTS .
Again ... this answer is only valid if I have assumed
the correct units for the numbers given in the question.
