Hi there!
Amit's reasoning is incorrect because multiplying a positive number by a negative number results in a negative result. The question also says that it is a charge to his account, which means that money is being taken away. Therefore, Amit's reasoning is incorrect because the bank is taking away money from him and his equation results in a positive value, instead of negative.
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!
