The First One
The Third One
The Forth One
The others result in a lower number than what they are supposed to be. The 3 correct ones end with the exact number of the equations solution number.
It works out that: y = 1 or 5 and therefore x = 5 or 1
Answer:
a = 2 
Step-by-step explanation:
Given
a = 
Multiply both sides by 9 ( the LCM of 3 and 9 ) to clear the fractions
3a = 7 ( divide both sides by 3 )
a =
= 2 
First you need to change 45 feet to 540 inches.
Now you can compare the two ratios:
1 : 25 and 25 : 540
We now need to change the second ratio to a unit rate:
25:540 as a unit rate would be 1 : 21.6 and this is steeper than the a 1 : 25 drop
So, your answer would be: pipe drops to much vertically to function properly