37:21= 815

$$3\frac{7}{8} : 2\frac{1}{15} = {\frac{31}{8}} : {\frac{31}{15}} = {\frac{31}{8}} \cdot {\frac{15}{31}} = {\frac{31 \cdot 15}{8 \cdot 31}} = {\frac{15}{8}} = 1\frac{7}{8}$$

Ответ: $$1\frac{7}{8}$$