Lokman contributed 3x (21 000)
Muin contributed 2x
Nordin contributed 5x
3x = 21 000
x = 21 000 / 3
x = 7 000
Total price of a land = 3x + 2x + 5x = 10x = 10 * 7 000 = 70 000
Profit = 85 000 - 70 000 = 15 000
Lokman's profit = 2y
Muin's profit = y
Nordin's profit = 3y
Total profit = 2y + y + 3y = 6y
6y = 15 000
y = 15 000 / 6
y = 2 500
Muin's profit = y = 2 500
Hope that helps.