I think the answer is c due to the word bag being plural but I’m not sure.
So r+c=42
c=4+r
subsitute c=4+r for r in r+c=42
r+4+r=42
add like terms
2r+4=42
subtract 4 from both sides
2r=38
divide both sides by 2
r=19
rob=19
subsitute r=19 for r in c=4+r
c=19+4
carly=23
Convert into like fractions -->
1/3 = 7/21 4/7 = 12/21
7+12 = 19
19/21 is spent therefore he has 2/21 left
