Question

Mark and his friends ordered 2 pizzas. The same size

Answer 1

We know that

They cut the first pizza into 6 equal slice---> each slice is 1/6 of a whole pizza

They cut the second pizza into 4 equal slices---> each slice is 1/4 of a whole pizza

Each person plans to get 2 slices

case 1) one slide pizza 1 and one slide pizza 2
total pizza=(1/6)+(1/4)----> (4+6)/24----> 10/24----> 5/12 of a whole pizza

case 2) two slides pizza 1
total pizza=2*(1/6)-----> 2/6----> multiply by 2-----> (2/2)*2/6---> 4/12 
so
4/12 < 5/12-------> Mark is correct