Answer:
[tex]c = 63\\b=21[/tex]
Step-by-step explanation:
Let number of pounds of cans collected by Amy = [tex]a[/tex]
Let number of pounds of cans collected by Bruce = [tex]b[/tex]
Let number of pounds of cans collected by Carlos = [tex]c[/tex]
As per question statement, total number of cans collected = 168
[tex]a+b+c=168[/tex] ..... (1)
Number of pounds collected by Bruce is [tex]\frac{1}{3}[/tex]rd of the pounds of cans collected by Carlos.
[tex]b = \dfrac{1}{3}c ..... (2)[/tex]
Number of pounds collected by Amy is equal to number of pounds collected by Bruce and Carlos combined.
[tex]a = b+c[/tex]
Using equation (2):
[tex]a = \dfrac{1}{3}c +c \\\Rightarrow a =\dfrac{4}{3}c ..... (3)[/tex]
Using equations (2) and (3) in equation (1), we get:
[tex]\dfrac{4}{3}c+\dfrac{1}{3}c+c =168\\\Rightarrow \dfrac{8}{3}c = 168\\\Rightarrow c =63[/tex]
Using equation (2):
[tex]b = \dfrac{63}{3} = 21[/tex]