Answer:
2
Step-by-step explanation:
m=7
1 blue jar = 21 marbles
1 blue jar = 3 red jars
Therefor
21 marbles= 3 red jars
(Now let m=1 red jar)
21= 3m
(Then sine we have 3m dived both sides by 3 to isolate the m)
21/3= 3m/3
7=m
