Answer: 
Step-by-step explanation:
Given
Girl has traveled 6 km from her house
She has covered
of the distance
Suppose the total distance is x

You would need 31 Vans for everyone to be transported.

For unorganized data, median is the middle value when the numbers are arranged in ascending order.
Let's proceed ~
In ascending order :
12, 13, 23, 26, 26, 35, 38, 44, 47
So, for given data... median is 26
Are you trying to make an algebraic equation?
x = # of trees
y = gal of water
It would be 30x = y