The salinity classifier

You will write functions that turn a mass of salt and a mass of water into a salinity, and then into a kind of water.

The idea. Salinity is the grams of salt in each kilogram of water, in parts per thousand. Inland waters are below $5$, the sea is $30$ to $35$, and hypersaline lagoons are above $100$.

Your tasks.

1. Finish salinity. It gives the grams of salt in each kilogram of water.
2. Finish kind. It gives "inland", "sea", "lagoon" or "other".
3. Finish count_sea. It counts the samples in the list that are sea water.