Answer:
The balance would be $160 from whatever it was before the 4 months.
Explanation:
Since the bank balance is being added by 40 for each month for 4 months, 4 * 40 is just 4*4 with an extra zero on the end. so that would be $160.
So if the balance before was $40, then the new balance after 4 months would be $200.
If there's no money previously, then there is now $160 after 4 months.
If there's a value before the $40 for 4 months, let me know and I will explain and tell you what it is.