According to the given question, 2/7 of the pizza order were pepper, it means that:
[tex]56\cdot\frac{2}{7}=16[/tex]16 of the pizzas were pepper. 19 of them were cheese and the rest veggie.
It means that the rest is:
[tex]56-16-19=21[/tex]21 pizzas were veggie. It means that the fraction of the pizza that was veggie is:
[tex]\frac{21}{56}=\frac{3}{8}[/tex]The answer is 3/8.