Shortcut Trick
Let the initial investments be 6x, 7x, and 9x.
Equating the scaling factors of the new ratio for P and Q: (6x + 30000) ÷ 8 = (7x + 25000) ÷ 9
⇒ 54x + 270000 = 56x + 200000 ⇒ 2x = 70000 ⇒ x = 35000
Value of 1 part in new ratio = (6 × 35000 + 30000) ÷ 8 = 30000
R's added amount = New Investment − Old Investment = (11 × 30000) − (9 × 35000) = 15000
∴ The correct answer is ₹15,000.
Alternate Method
Given:
Initial ratio of investments of P, Q, and R = 6 : 7 : 9
Amount added by P = ₹30,000
Amount added by Q = ₹25,000
New ratio of investments of P, Q, and R = 8 : 9 : 11
Formula Used:
Ratio = Value of Part 1 ÷ Value of Part 2
Partner P
Partner Q
Partner R
Initial: 6x
= 210,000
Initial: 7x
= 245,000
Initial: 9x
= 315,000
Final: 8 parts
= 240,000
Final: 9 parts
= 270,000
Final: 11 parts
= 330,000
Amount added by R = 330,000 − 315,000 = 15,000
Calculations:
Let the initial investments of P, Q, and R be 6x, 7x, and 9x respectively.
After 1 year, new investments of P and Q are (6x + 30000) and (7x + 25000).
According to the given new ratio for P and Q:
⇒ (6x + 30000) ÷ (7x + 25000) = 8 ÷ 9
⇒ 9 × (6x + 30000) = 8 × (7x + 25000)
⇒ 54x + 270000 = 56x + 200000
⇒ 56x − 54x = 270000 − 200000
⇒ 2x = 70000
⇒ x = 35000
Initial investment of R:
⇒ 9x = 9 × 35000 = 315000
New investment of P:
⇒ 6x + 30000 = 6 × 35000 + 30000 = 240000
Since the new ratio for P is 8 parts, we can find the exact value of 1 ratio part:
⇒ 1 part = 240000 ÷ 8 = 30000
New investment of R:
⇒ 11 parts = 11 × 30000 = 330000
Amount added by R:
⇒ New investment − Initial investment
⇒ 330000 − 315000 = 15000
∴ The correct answer is ₹15,000.
Additional Information
Partnership Ratios
Profit in a partnership is distributed in proportion to the product of the capital invested and the time period of investment. (Profit Ratio = C1 × T1 : C2 × T2).
Changes in Capital
When a partner adds or withdraws capital midway through the term, the total investment weight is calculated by multiplying each active capital amount by the respective time duration it remained invested.
Ratio Equating Method
When fixed amounts are added to or subtracted from components of an original ratio to form a new ratio, setting up a cross-multiplication equation between any two quantities helps efficiently find the common scaling factor.