So, here you're trying to figure out how many balls are purchased each year. One can assume that the # of balls purchased is the number of balls lost (replenishment rate).

Now let's work backwards:

I know the population of players in Portugal, but now I need to know **how many balls this whole population needs**. If I get the **# of balls lost each year**, on average, per player, then **I can multiply this by the whole population of players get to total demand**.

The #** of balls lost each year per player** can be found by figuring out **# of games played** per year times **# of balls lost each game**.

So, here you're trying to figure out how many balls are purchased each year. One can assume that the # of balls purchased is the number of balls lost (replenishment rate).

Now let's work backwards:

I know the population of players in Portugal, but now I need to know **how many balls this whole population needs**. If I get the **# of balls lost each year**, on average, per player, then **I can multiply this by the whole population of players get to total demand**.

The #** of balls lost each year per player** can be found by figuring out **# of games played** per year times **# of balls lost each game**.