Question 97912
Jane's speed 1000 in 6 hours ie 500/3 in one hour...2000/3 in 4 hours
brother can do 1000-(2000/3)=1000/3 in 4 hours
means...
100/3 in 4 hours
1000 in 12 hours 
500 in 6 hours
So Brother can stuff 500 in 6 hours
OK