"Sarah and four friends", this means that we have a total of 5 persons.
They have four rolls of ribbon to share evenly.
1- This represents division as they have to equally divide four rolls among them.
2- The share of each can be calculated by dividing the four rolls they have by the five of them as follows:
share of each = 4/5 rolls = 0.8 rolls
The initial value is 309.35
It means that in the year 2010 (starting year) the population was 309,350,000 people or written another way "309.35 million". The second way is more short so probably the more preferred method.
To find the value 309.35, simply look at the table under the value t = 0.
2.23606797749979
or round it to 2.2