the question in English
50 t-shirts were sold at 10€ each. What benefit was obtained if the t-shirts were bought at 7€ each?
Let
x---------> the benefit in euros
we know that
[tex]x=50*10-50*7[/tex]
[tex]x=50*(10-7)[/tex]
[tex]x=50*3[/tex]
[tex]x=150\ euros[/tex]
therefore
the answer is
The benefit is equal to [tex]150\ euros[/tex]