A + b + c = 168
b = 1/3c
a = b + c....a = 1/3c + c = 4/3c
now we sub
4/3c + 1/3c + c = 168
8/3c = 168
c = 168 * 3/8
c = 504/8
c = 63 <=== Carlos collected 63 lbs
a = 4/3c
a = 4/3(63)
a = 252/3
a = 84 <== Amy collected 84 lbs
b = 1/3c
b = 1/3(63)
b = 63/3 <== Bruce collected 21 lbs
b = 21
Answer:

Step-by-step explanation:
Given
The attached graph
Required

This is the point where

On the attached graph;
when 
Hence:

We are given the equation:
F = 2.25+0.2(m-1)
where:
F is the fare
m is the number of miles.
In question 7, we are given that the fare (F) is equal to $6.05 and we need to get the number of miles. To do so, we will simply substitute with the fare in the given equation and solve for the number of miles (m) as follows:
F = 2.25 + 0.2(m-1)
6.05 = 2.25 + 0.2(m-1)
6.05-2.25 = 0.2(m-1)
3.8 = 0.2(m-1)
3.8/0.2 = m-1
19 = m-1
m = 19+1
m = 20 miles
Number 8 is exactly the same, but we will substitute F=7.65 and again solve for m