Chapter 3 - Adding and Subtracting Fractions - 3.2 Least Common Multiples - 3.2 Exercises - Page 213: 54

$12000$.

$\frac{53}{600}, \frac{115}{4000}$ $600 = 2 \cdot 2 \cdot 2 \cdot 3 \cdot 5 \cdot 5$ $4000 = 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 5 \cdot 5 \cdot 5$ LCM $= 2 \cdot 2 \cdot 2 \cdot 2 \cdot 2 \cdot 3 \cdot 5 \cdot 5 \cdot 5 = 12000$.