Maranchyse answer won't work for 40 and 30 case. The the idea is rite. This is my answer First shift: 11 oranges @ 1 Rs person no. sold money collected no. remained A(100) 99 9 1 B (80) 77 7 3 C (60) 55 5 5 D (40) 33 3 7 E(30) 22 2 8 Second Shift: 1 orange @ 1 Rs person sold total money A 1 9+1=10 B 3 7+3=10 C 5 5+5=10 D 7 3+7=10 E 8 2+8=10 This idea works for any number multiple of 10 and less than or equal to 100.