The value of the constant of proportionality in the expression c=1.1 b is 1.1.
Given to us
The total cost, c, in dollars, of b bottles of water, is c = 1.1b.
<h3>What is the constant of proportionality? </h3>
The constant of proportionality is plugged into an expression when the proportionality is been removed from the expression.
As the total cost is dependent on the number of bottles that is been purchased, therefore,

Removing the proportionality, we will get,

where c is the total cost, b is the number of bottles,
Now compare the two equations,
c = kb
c = 1.1 b
Hence, the value of the constant of proportionality in the expression c=1.1 b is 1.1.
Learn more about Proportionality:
brainly.com/question/5837592