Three hikers A, B, and C each start with ₹ 50 and agree to share trip expenses equally. At the end, A has ₹ 20 left, B ₹ 30, and C ₹ 40. By how much must they settle their accounts?

Introduction / Context:
With equal expense sharing, each person should end up having spent the same amount. Compute each person’s actual spending and compare with the fair share. Transfers should move money from those who underpaid to those who overpaid.

Given Data / Assumptions:

• Initial cash: ₹ 50 each (total ₹ 150)
• Final cash: A ₹ 20, B ₹ 30, C ₹ 40
• Total spent = initial total − final total

Concept / Approach:
Actual spent by a person = initial − final. The fair share is total spent divided by 3. Compare each person’s actual spend to the fair share and settle the differences with a single minimal transfer.

Step-by-Step Solution:
Total spent = 150 − (20 + 30 + 40) = 150 − 90 = ₹ 60Fair share = 60 / 3 = ₹ 20 eachA spent = 50 − 20 = ₹ 30 (overpaid ₹ 10)B spent = 50 − 30 = ₹ 20 (fair)C spent = 50 − 40 = ₹ 10 (underpaid ₹ 10)Settlement: C must pay ₹ 10 to A

Verification / Alternative check:
After transfer, each effectively spends ₹ 20. Totals remain consistent and no further transfers are needed.

Why Other Options Are Wrong:
They either move money in the wrong direction or between the wrong pair, failing to equalize actual spending to the fair share.

Common Pitfalls:
Confusing final balances with spending; always compute spending as initial − final, not the other way around.

Final Answer:
C must pay ₹ 10 to A