800guy

First i do agree that the answer is 12 but the only way i can think of speeding it up is as follows if for A B S=? S= ? T= t then T= t+6 D= d D= 9d/10 Now S=? S= ? T= t still but now T= t-2 D= d still D= 7d/10 ( so if d =480 as we know then it is 7/10 x 480) now you have 2 equations for b which is w...