1. The problem statement, all variables and given/known data

Hi

I need some help with this problem. It reads this way:

The manufacturer of a digital ammeter quotes its uncertainty as plus-minus 1.5% plus-minus 2 digits.

a) Determine the uncertainty in a constant reading of 2.64A

b) The meter is used to measure the current from a d.c power supply. The current is found to fluctuate randomly between 1.58A and 2.04A. Determine the most likely value of the current, with its uncertainty.

2. Relevant equations

uncertainty as plus-minus 1.5% plus-minus 2 digits.

3. The attempt at a solution

Solving (a)

2.64 x 1.5% = 0.0396

1.5% x 2 = 0.03

Adding the above =0.0696

The answer in my physics book is plus - minus 0.06A. Can anyone kindly clarify way? I know the number of significant figures determines the uncertainty. Can the answer not be 0.07A? (After rounding up)

Solving (b)

I am not sure how to being. Since uncertainty is the range of values, I decided to find the range

So, 2.04-1.58 = 0.46A

But not sure how to progress further. Any suggestions? (Please bear in mind I study independently)