5 1-:1-

$$1{\frac{51}{93}}: 1{\frac{5}{31}} = {\frac{144}{93}}: {\frac{36}{31}} = {\frac{144}{93}} \cdot {\frac{31}{36}} = {\frac{36\cdot4\cdot31}{31\cdot3\cdot36}} = {\frac{4}{3}} = 1{\frac{1}{3}}$$

Ответ: 1 1/3