Question

2. Pat is six years older than twice his Cousin Zach’s age. The sum of their ages is less than 36.

Answer 1

Let denote Pat's age with P and Zach's age with Z.
We know the following facts:
1.Pat is six years older than twice his Cousin Zach’s age. We can rewrite this statement as:
P=2*Z+6
2. The sum of their ages is less than 36.
P+Z<36
In order to find the greatest age that Zach could be we should find for which Z 
P+Z=35 (the first whole number smaller than 36) 
P=35-Z
35-Z=2*Z+6
35-6=3Z
29=3Z
Z=29/3
Z=9

Answer 2

P = Pat
C = Cousin Zach

2C + 6 = P
2C + 6 - 6= P - 6
2C = P - 6
2C/2 = P - 6/2
C = P - 3
C + 3 = P
so (C + 3) + P < 36
 (C + 3 - 3) + P < 36 - 3
C + P < 33

Can you see what I am doing?