Answer: 200 US dollars
At bank A:
Exchange rate: £1 = $1.27
So, at bank A, you would receive 1.27x1.27xin US dollars.
At bank B:Exchange rate: £1 = $1.30
Transaction fee: £6
The amount in US dollars at bank B would be (1.30x−6)(1.30x−6).
To find the point where you would receive more US dollars at bank A than at bank B, set up the inequality:1.27x>1.30x−6
Now, solve for x:
0.03x<6
x<6/0.03 x<200x<200
So, if you exchange more than £200, you will receive more US dollars at bank A than at bank B.