Can some one help me with this i don't under stand it

Lenny and Thad spend a certain amount of money from their money box each month to buy comic books.

The table shows the relationship between the amount of money (y) remaining in Lenny's money box and the number of months (x):

The equation shows the relationship between the amount of money (y) remaining in Thad's money box and the number of months (x):

Function 2:
y = −12x + 80

Which statement explains which function shows a greater rate of change?

Question

Can some one help me with this i don't under stand it 

Lenny and Thad spend a certain amount of money from their money box each month to buy comic books. 

The table shows the relationship between the amount of money (y) remaining in Lenny's money box and the number of months (x):


The equation shows the relationship between the amount of money (y) remaining in Thad's money box and the number of months (x): 

Function 2: 
y = −12x + 80 

Which statement explains which function shows a greater rate of change?

anonymous · Answer

I don't know sorry.....

jacob902 · Answer

so lets make the table:

number of months.  (the x)             amount in dollars.  (the y)
             1                                                  75
             2                                                  60
             3                                                  45
             4                                                  30

jacob902 · Answer

this is the first function represented in the table. Can you tell me what is happening to the amount after each month?

anonymous · Answer

in the first function it is decreasing by 15
in the second function it is decreasing by 12

jacob902 · Answer

ok