The mechanical advantage (MA) of a lever can be calculated using the formula:
\[ \text{MA} = \frac{\text{Distance from fulcrum to effort}}{\text{Distance from fulcrum to load}} \]
In this case, the distance from the fulcrum to the effort force is 15 meters, and the distance from the fulcrum to the load force is 5 meters. Plugging in the values:
\[ \text{MA} = \frac{15 , \text{m}}{5 , \text{m}} = 3 \]
Thus, the mechanical advantage is 3.