Hope this can help you. I tried to solve each one out and I tried to write notes on how I got the equation and the answer. Message me if you can't read something, my handwriting tends to be messy :)
Answer:

And solving we got:



Step-by-step explanation:
For this case we can define the following notation:
represent the width
And we want a maximum error of 0.0003 so we can set up the following equation:

And solving we got:


