
Answer:
70 amps
Step-by-step explanation:
The current I is inversely proportional to the resistance R
I=k/R Â (k is the constant of proportionality)
A) Â I=210 amperes
   R=4 ohms
I=k/R
k=I×R
k=210×4=840
B) Â Â R=12 ohms
   k=840
  I=k/R
  I=840/12=70 amperes