Robinson and Friday are the only people on Despair, a small island. They both produce grain and meat. Let G denote the quantity of grain, and M denote the quantity of meat. The following equations summarize their production possibility curves (PPCs) per week.

---------------------------------

Robinson: G = 21 7M

Friday: G = 148 8M

---------------------------------

Suppose Despair is a closed economy. If Robinson and Friday would like to jointly consume 16 units of meat per week, they would be able to jointly consume a maximum of [Answer] units of grain per week.

(In decimal numbers, with two decimal places, please.)