Answer:
2/21
Step-by-step explanation:
We start out with a full tank. Once the trucks take from it, it is down to 1/3 of a tank. Therefore,
[tex]\frac{3}{3} -\frac{1}{3} =\frac{2}{3}[/tex]
So the trucks took 2/3 of the gas.
If there were 7 trucks and we need to know how much of that 2/3 was taken by each truck, we divide 2/3 by 7:
[tex]\frac{\frac{2}{3} }{7}[/tex]
When dividing fractions, we bring up the lower fraction and flip it and multiply:
[tex]\frac{2}{3}*\frac{1}{7}=\frac{2}{21}[/tex]