Answer:
Dependent variable: time(months) or 
Independent variable: 6
Step-by-step explanation:

(h=height)
Step-by-step explanation:
-(38/21)
that is the answer
We can add 1/6 & 1/3 together to find out the total amount of crackers that were eaten:
1/6 + 1/3 (Find the Common Denominator. In this case it is 6.)
= 1/6 + 2/6
= 3/6 (Now find the Lowest Terms. Both 6 & 3 divide into 3)
= 1/2 (In Lowest Terms)
This means that 1/2 of the Crackers have been eaten.
1/2 of 18 = 9
Therefore, Bob has 9 Crackers left.