Added question

book/pages/moo.md

@@ -12,9 +12,9 @@ with:
 - Constraints and bounds as for single-objective optimization problems.
 
 ## Model
-Three different ways of solving multi-objective optimization problems were introduced:
+Three different ways of solving multi-objective optimization problems were introduced, which all effectively convert the problem to a single-objective optimization problem:
 
-1. Weighted objective function: setting pre-determined weight on the two objectives, effectively converting the problem to a single-objective optimization problem. In general this requires the two objectives to have a comparable unit:
+1. Weighted objective function: setting pre-determined weight on the two objectives. In general this requires the two objectives to have a comparable unit:
 
 ```{math}
 :label: multi_objective_optimization_weighted
@@ -35,6 +35,8 @@ Three different ways of solving multi-objective optimization problems were intro
  \mathop {\min }\limits_x \left( {{\delta }_{i}} \cdot f_{1,\text{normalized}}\left( x \right) +  \delta_j \cdot f_{2,\text{normalized}}\left( x \right) \right)
 ```
 
+All of these methods could also be applied to problems which include more than two goals.
+
 ### Normalize objective functions
 Normalizing the objectives functions can be done by setting the domain of every goal $f$ between $0$ and $1$ by finding (or estimating) the lower and upper bounds for these objective functions within the domain:
 
@@ -46,8 +48,13 @@ Normalizing the objectives functions can be done by setting the domain of every
 \end{align}
 ```
 
+:::{card} Test yourself
+<iframe src="https://tudelft.h5p.com/content/1292259181041373527/embed" aria-label="MOO models" width="1088" height="637" frameborder="0" allowfullscreen="allowfullscreen" allow="autoplay *; geolocation *; microphone *; camera *; midi *; encrypted-media *"></iframe><script src="https://tudelft.h5p.com/js/h5p-resizer.js" charset="UTF-8"></script>
+:::
+
 ## Method
 
+Because the models are all single-objective, we can use our earlier methods to solve these problems.
 
 ## Questions, discussions and comments
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