Let the number of boxed lunches ordered be b
Let the total cost in dollars and cents be c
The given proportionality between them is c=9.8b.
The constant of proportionality from the number of boxed lunches to the total cost in dollars and cents is the same as the ratio of the number of boxed lunches to the total cost in dollars and cents is the same as the ratio
Simply put b : c;
So the constant of proportionality is 1/9.8