12 - 7 is 5. you can count down 7 times from 12 like: 12, 11, 10, 9, 8, 7, 6, 5.
Bank A because in 12 months, the rate will be more than the annual rate in Bank B. You will save more in Bank A.
I hope this helps!
1st year= 18000 x 0.85 = 15300
2nd year= 15300 x 0.85 = 13005
3rd year= 13005 x 0.85= 11054.25
