The L-shapes grow by the same rule from one figure to the next. How many squares will Fig 15 have?

Fig 1 has 3 squares, Fig 2 has 5, Fig 3 has 7: each figure adds 2 (one on each arm). Fig $n$ has $2n+1$ squares, so Fig 15 has $2\times 15+1=31$. (45 wrongly multiplies 3 by 15.)