post是柱子的意思～
=== 第一题 我解释不清楚 给你google了下
Let x = my age,
y = your age
The age difference always remains constant therefore I will always be x-y years older than you.
When I was your age,i.e my age was "y" years,your age will be y - (x-y) = 2y-x years.
But at that time i was twice as old as you.i.e,y = 2*(2y - x)
=> y = 4y - 2x
=> 3y = 2x
Or my age = 1.5 * your age.