Answer
Find out the what fraction of the sandcastle did they build together .
To prove
Let us assume that the fraction of the sandcastle they build together be x .
As given


Than the equation becomes

L.C .M of (3,7) = 21
solving


Therefore the fraction of the sandcastle did they build together be

Hence proved
Yes you are correct B is the right answer
Answer:
20 games
Step-by-step explanation:
(12/x)=(60/100)
12*100=1200
60x=1200
x=20
99 km ... 9 liters
x km ... 12 liters
If the relationship is proportional, we have

from where
The answer is 132 kilometers.