Ryan paid $42 for a total of 26 pizzas and chicken pies altogether. His friends ate 16 pies and the number of pies left was 0.25 of the number of pizzas. Each pie cost $2 less than a pizza. How much more did he pay for the pizzas than the pies he bought?
The number of pies left was 0.25 * 26 = <<0.25*26=6.5>>6.5 pies.
He bought 26 - 6.5 = <<26-6.5=19.5>>19.5 pizzas.
Each pizza cost $42/ 26 = $<<42/26=1.6153846153846154>>1.61.
Each pie cost $1.61 - $2 = -$0.39 than a pizza.
So, the price of one pie is $1.61 - $0.39 = $<<1.61-0.39=1.22>>1.22.
He paid $1.61 * 19.5 = $<<1.22*19.5=23.739999999999998>>23.74 less for the pies.
Thus, Ryan paid $42 - $23.74 = $<<42-23.74=18.26>>18.26 more for the pizzas than the pies. Answer: \boxed{18.26}.