the current i in a wire varies directly as the voltage v and

the current (i) in a wire varies directly as the voltage (v) and inversely as the resistance (r). If the current is 27.5 amps when the voltage is 110 volts and the resistance is 4 ohms, find the current when the voltage is 200 volts and resistance is 16 ohms. round your answer to two decimal places.
...... lb

Solution

We have i = kv/r where i is the current in the wire, v, the voltage, r , the resistance and k is the constant of proportionality. Then 27.5 = k*110/4 so that k = 27.5 *4/110 = 1. Now, when v =200, and r = 16, we have i = kv/r = 1*200/16 = 12.5 amps.