A, B, and C invest in a business in the ratio 2:3:5. After 4 months, A increases his capital by 50%, B decreases his capital by 1⁄3, and C leaves the capital unchanged. At the end of the year, if the total profit is Rs. 33,000, find the share of B.

- (a)Rs. 7,700
- (b)Rs. 8,000
- (c)Rs. 9,000
- (d)Rs. 10,500
Answer
Why
Correct — A. Profit is shared in the ratio of capital × months (unit-months). Take the starting capitals as 2, 3 and 5 units.
After 4 months: A becomes 2 × 1.5 = 3, B becomes 3 × 2⁄3 = 2, C stays 5
A's unit-months: 2 × 4 + 3 × 8 = 32
B's unit-months: 3 × 4 + 2 × 8 = 28
C's unit-months: 5 × 12 = 60
Add: 32 + 28 + 60 = 120, so one unit-month earns 33,000 ÷ 120 = Rs. 275
B's share: 28 × 275 = Rs. 7,700 → option (a)
Why the others are wrong
- (b)Rs. 8,000 — Rs. 8,000 would need B to hold 8⁄33 of the 120 unit-months, about 29.1. B holds exactly 28: 12 in the first four months and 16 in the last eight.
- (c)Rs. 9,000 — Rs. 9,000 is 3⁄11 of the profit, a larger slice than B earns. B holds 28 of the 120 unit-months, which is 7⁄30, and 7⁄30 of 33,000 is Rs. 7,700.
- (d)Rs. 10,500 — Rs. 10,500 is more than B's starting slice, 3⁄10 × 33,000 = Rs. 9,900. B cut his capital while A raised his, so B's slice must shrink below 3⁄10, not grow.
Concept
In a partnership the profit is split in proportion to capital × time. Count it in unit-months: one unit of capital held for one month.
When a partner changes capital midway, split his year at the change and add the two products.
A percentage or fraction change acts on the partner's own capital: A's 50% rise turns 2 units into 3, and B's cut of 1⁄3 turns 3 units into 2.
Check: A gets 32 × 275 = Rs. 8,800 and C gets 60 × 275 = Rs. 16,500. With B's Rs. 7,700 the three add to Rs. 33,000.
Key facts
- Profit ratio = ratio of (capital × months) for each partner.
- A 50% increase multiplies a capital by 3⁄2.
- A decrease of 1⁄3 multiplies a capital by 2⁄3, not by 1⁄3.
- A change after 4 months of a 12-month year leaves the new capital in place for 8 months.
Study next
Common traps
- Applying the new capitals for the whole year and ignoring the first four months at 2 : 3 : 5.
- Reading 'decreases by 1⁄3' as 'decreases to 1⁄3', which turns B's 3 units into 1 instead of 2.
Here a ratio and two percentage changes stand in for rupee amounts.
A mid-period change of capital also decides 14 Sep 2025, 12:30, Quant Q.7, which starts from the same 2 : 3 : 5 ratio with two withdrawals over 18 months, and 15 Sep 2025, 16:00, Quant Q.4, where Kapil withdraws ₹40,000 six months in.
Related PYQs
No directly related past PYQ was found.