It will take 4 hours, this is because it said it adds 1000 after two hours, and it will add another 1000 two hours later which will give you your answer of four hours
I like point point form because it doesn't fail in the no slope case. The line through (a,b) and (c,d) is
(c-a)(y-b) = (d-b)(x-a)
Point slope form is almost the same,

1. (a,b)=(4,0),(c,d)=(-2,1)
y - 0 = (1 - 0)/(-2 - 4) (x - 4)
Answer: y = (-1/6)(x-4)
2.
y - -2 = (3 - -2)/(5 - -3) (x - -3)
Answer: y + 2 = (5/8) (x+3)
3.
y - 1 = (4 - 1)/(3 - -5) (x - -5)
Answer: y - 1 = (3/8) (x+5)
The answer to this problem is the letter "A" which is "Multiply by 3, then add 2"
and can be written a N = 3n + 2
At first, we have initial value such n = 1
Then the second value is:
N = 3*1 + 2
N = 5
The third value is:
N = 3*5 + 2
N=17
The next values are:
N = 3*17 + 2
N= 53
The letter "A" is the inductive reasoning to the given sequence.
If it is fractions then the answer is -7/15. Think of as 8/15 - 1/15 except the answer is a negative number