At a pet store, there are 30 aquariums. Of the 30, 20 have fresh water with 15 fish in each. The other 10 aquariums have salt water fish with 6 fish each. Which equation could be used to find f, the total number of fish at the pet store?

The pyraminx is a rubik's cube-type toy in the shape of a tetrahedron. the pyraminx shown below has edges 15\,\text{cm}15cm long and vertical height h=12.2\,\text{cm}h=12.2cm. the triangle drawn with dashed lines is a right triangle. what is the distance rr? round your answer to the nearest tenth.