x-x=0 so whole is zero

3
Different method

P is main craft now X and P goes till 1/6 and X refuels P and return back and refuelled and go together with y (opposite direction ) with get refuel from X at point 5/6 (X mean while goes back refueld and come back with Z)then Y goes to 4/ 6 and  refuel P then both come to 5/6 where they get fueled from X and Z  to come back to start.
Genius is back xd

(1+2+4……………………………………………2^97 +1)/(2+4+8+16+32+64………………….2^98 +2)
it is  1/2 see clearly
suppose I named  100th person as 100 and so on
suppose steve sit on 99th person seat then there are 2 case 1 favorable
now if he sit on 98 then if 98 sit on 99 then similar case as before so 2 case 1 favorable if 98 sit on 100 1 case 0 favorable if 98 sit on 1 then 1 case 1 favourable so total 4 case 2 favourable
if he sit on 97 then if 97 sit on 98 then similar to previous 4case 2 favourable if 97 sit on 99 then similar to first case when steve sit on 99 2 case 1 favourable if 97 sit on 1, 1 case 1 favourable  and if he sits on 100 then 1 case 0 favourable so total 8 case 4 favourable

this thing goes on

please understand when I used number referring to person and when to seat
as it would have been too long to write
u know what to do if my answer is write