Concept: Total amount of sand in the 3 boxes did not change after each transfer of sand from one box to another.

Strategy: Working backwards

At the end (After Transfer from C to A):

Each box –> 360g / 3 = 120g

Before Transfer from C to A:

4 units out of 5 units of C –> 120g

Amount of sand transferred to A –> 120g / 4 = 30g

Amount of sand in A –> 120g – 30g = 90g

Amount of sand in C –> 120g + 30g = 150g

Before Transfer from B to C:

2 units out of 3 units of B –> 120g

Amount of sand transferred to C –> 120g /2 = 60g

Amount of sand in C –> 150g – 60g = 90g

Amount of sand in B –> 120g + 60g = 180g

At first (Before Transfer from A to B):

5 units out of 6 units –> 90g

Amount of sand transferred to B –> 90g / 5 = 18g

Amount of sand in B –> 180g – 18g = 162g

Amount of sand in A –> 90g + 18g = 108g

**Answer: A: 108g, B:162g and C: 90g**