🔍 Reverse: Find the Unknown
2 exam question types, fully solvedSometimes the profit ratio is handed to you and the unknown is hidden inside — a missing investment, a missing number of months, or the total profit. The same one rule still applies; you just run it backwards.
Everything starts from the master equation:
• Missing time or capital: put in everything you know and cross-multiply for the one blank.
• Capital from profit and time: rearrange to capital , so . Divide profit by time — do NOT multiply.
• Find the total from one share: a share . Get one part from the known share, then multiply by the sum of all parts.
Shortcut: if the profit ratio already equals the (simplified) time ratio, the capitals are equal — , no working needed.
Equal capital, invested for 6 and 9 months. The profit ratio is the time ratio: .
Q1A and B invest in the ratio 4 : 3. A's profit share is ₹8,000. The total profit is:
Q2X invests for 6 months and Y for 9 months, with equal capital. The profit ratio X : Y is:
Q3A, B and C invest in the ratio 2 : 3 : 5. C's share is ₹10,000. The total profit is:
Real exam questions — Find the Unknown
2 question types · 8 solved examples from real SSC papersRun the formula backwards: from the profit ratio recover a missing time, a missing capital, or the total profit. Cancel a common factor before you solve.
• Missing capital style — just cross-multiply.
• Capital ratio from profit and time: capital , so .
Shortcut: if profit ratio equals the (simplified) time ratio, the capitals are equal, 1 : 1.
P and Q invest ₹40,000 each, for 6 months and 9 months respectively. Find the profit ratio P : Q.
X and Y invest ₹25,000 and ₹30,000 for 8 months and 6 months respectively. Find the profit ratio X : Y.
A invested ₹30,000 and B invested ₹20,000. The profit at year end is shared equally. For how many months did B invest (A invested for 12 months)?
A and B invest for 6 months and 9 months respectively. The profit ratio is 1 : 2. Find the capital ratio A : B.
