Answer:
C
Step-by-step explanation:
Charlene has 8 more dollars so you would have to add it all together to get 86.
Try breaking these into sections.
Twice: 2 times
The sum of: add
A number: choose a variable, like x
---Thus "the sum of a number and 4" becomes "add x and 4" which, mathematically, is "x+4"
-----Continuing to put it all together, "Twice the sum of a number and four" becomes "2 times (x+4)" which, mathematically, is "2(x+4)"
Is: equals
-------"Twice the sum of a number and four is" becomes "2(x+4)="
23 less than: subtract 23. This one tends to trick people; "23 less than" will become "__ - 23", NOT "23 - __"
three times the number: 3 times x
---"23 less than three times the number" becomes "subtract 23 from 3 times x" which, mathematically, is "3x-23"
-------So the final phrase: 2(x+4)=3x-23"
The number of tops on the 6th day based on the exponential model is 64, and the number of tops on the 6th day based on the linear model is 17.
<h3>What is an exponential function?</h3>
It is defined as the function that rapidly increases and the value of the exponential function is always a positive. It denotes with exponent 
where a is a constant and a>1
First day class collected = 2 tops
Third day class collected = 8 tops
The exponential function can be modelled:

D(1) = 2 (first day)
D(3) = 8 (third day)
D(6) = 64 (sixth day)
The linear function can be modeled:
D(N) = 3N -1
D(1) = 2 (first day)
D(3) = 8 (third day)
D(6) = 17 (sixth day)
Thus, the number of tops on 6th day based on exponential model is 64, and the number of tops on the 6th day based on the linear model is 17.
Learn more about the exponential function here:
brainly.com/question/11487261
#SPJ1