Question

Six friends share 3 pizzas one friend leaves how much more will the other 5 friends get

Answer 1

3 divided into 6 would be 0.5 pizzas each but since one left you divide 3 by 5 and you get 0.6

Answer 2

If 6 friends share 3 pizzas then each friend would get 1/2 of a pizza but if one leaves and 5 friends share the pizzas then each would get 3/5 of a pizza. 3/5-1/2=6/10-5/10=1/10 
so each person gets 1/10 more