Answer:
Step-by-step explanation:
Let suppose that each bus has the same capacity and exists a direct proportionality between the amount of people that is transported and the number of buses:
Where 
is the proportionality constant, which is equivalent to the maximum capacity of each bus. In that case, the quantity of people that is transported on 40 buses is:
For this problem I got y= 1/6x
2d+1/6=2d+6 (I distributed the 6 to what was in the parentheses)
2d-2d=6-1/6 (I subtracted 2d from both sides to get the variables on one side and 1/6 from both sides to get the variables by themselves)
0=35/6 (combined like terms)
0=35/6 is an untrue statement so x doesn't exist
