Answer :
it would be 4 toppings beacause 7+0.75(4 toppings)=10.00 for tonys pizza and 8+0.50(4 toppings)=10.00 for marias pizza
The answer would be 4 because if you take 7+(.75*4)=10 and 8+(.5*4)=10 so because 10=10 the 4 is correct. For finding these kinds of things sometimes the quicker way to do it is guess and check meaning guess random numbers then check it and revise. Enjoy!=)