To solve this question set, it is absolutely critical to mark the different sections of the Venn diagram appropriately or you may stand to get confused.

Let *F* denote French, *G* denote German and *R* denote Russian.

Total number of students surveyed = n(*U*) = 100% = 500

So, it follows that n(*F*) = 51%, n(*G*) = 48% and n(*R*) = 52%

To represent the fact that there are students who wanted to learn more than one language, we should use the intersection notation as it represents elements common to two or more sets. As per the information given in the question statement, we have:

n(*F * ∩ *G*) = 21%, n(*G *∩ *R*) = 23%, n(*R *∩ *F*)

= 24%, n(*F *∩ *G *∩ *R*) = 12%

As per the diagram, it is seen that:

The percentage of students who wanted to learn *F* and *G* only = the percentage of students who wanted to learn both *F* and *G* – the percentage of students who wanted to learn all 3 languages

= n(*F *∩ *G*) - n(*F *∩ *G *∩ *R*)

= (21 - 12)%

= 9%

Similarly,

The percentage of students who wanted to learn *G* and *R* only

= n(*G* ∩ *R*) - n(*F *∩ *G *∩ *R*)

= (23 - 12) %

= 11%

The percentage of students who wanted to learn *R* and *F* only

= n(*R *∩ *F*) - n(*F *∩ *G *∩ *R*)

= 12%

Now that we have all this information from the common data, we can go ahead and answer the question.

The percentage of students who wanted to learn *G* only = The percentage of students who wanted to learn *G* - the percentage of students who wanted to learn *G* and *R* only - the percentage of students who wanted to learn *F* and *G* only - the percentage of students who wanted to learn all 3 languages

$= (48 - 11 - 9 - 12)\% $

$= 16\% $

Therefore, the number students who wanted to learn German only,

$= 0.16 × 500$

$= \textbf{80}$