10 days for A by 1,000 m = 2 days 5x2=10 And for B it will be 9.75 kilometers on the thrid day because of .75x3=2.25 then put 7,500 meters to 7.5 kilometers then 7.5+2.25=9.75 kilometers on the third day. For C it would be plan B because it would 20 days to get 20 kilometers for A but plan B is two days ahead of A by taking 7.5x3=22.5=20 days 22.5-.75=21.35 21.35-.75=20.60. Hope this helps because it took me a while.