We know that a pack of 5 pencils, including the package, has to be within 60 grams and 95 grams.
If P is the weight of each pencil and the package weights 15 grams, the weight of the pack is:

Then, we can start by writing the inequality for the pack as:

Each pencil can weight between 9 and 16 grams inclusive, so a pencil can have a mass of 10.5 grams.