Answer:
 120V
Step-by-step explanation:
Given parameters: 
Current = 6A
Resistance = 20Ω 
Unknown: 
Voltage = ? 
Solution: 
According to ohms law; 
 V = IR 
Where V is the voltage
 I is the current
 R is the resistance
 Now, insert the parameters and solve; 
 V = 6 x 20 = 120V