Can anyone give me some guidance on this?
Sam writes down the numbers 1, 2, 3, ..., 99
(a) How many digits did Sam write, in total?
(b) Sam chooses one of the digits written down, at random. What is the probability that Sam chooses a 0?
(c) What is the sum of all the digits that Sam wrote down?
I expect you can work out (or count) part a just as well as any of us can.
There are 9 individual digits then 2 digits for each number from 10 to 99. How many is that?
Part b. Count how many zeros there are and put that number of the total number of digits.
Part c. Do the other 2 parts then look for patters that you can add together.