Question 11

Explanation

First, we calculate the weight of chocolate powder needed to make $10$ cakes using the given ratio. The ratio of chocolate to vanilla is $3 : 2$, and the weight of vanilla is $30$ grams:

Next, we calculate the requirement for $50$ cakes. Since $50$ cakes is $5$ times $10$ cakes, the weight of chocolate powder needed is also $5$ times as much:

So, the weight of chocolate powder needed to make $50$ cakes is $225$ grams.