Consult the figure. To find the length of the span of a proposed ski lift from A to B, a surveyor measures the angle DAB to be and then walks off a distance of to C and measures the angle ACB to be 15 degrees What is the distance from A to B?

They both will have 128 stamps in 6 months.
Equation- 56+12x= 80+8x
solution x=6 (in 6 months they will have same stamps)
plug 6 into both equations to figure out how many stamps.
56+12*6=128 (xians equation) 
80 +8*6= 128 (kais equation) 
Hope this helped!