A job worth ₹36,000 is taken on jointly by Rajan and Sanjay. Rajan alone would need 30 days and Sanjay alone 45 days, and both work on it every day until it is done. The money is divided in proportion to the work each does. How much does Sanjay earn?

Rajan does 1/30 of the job a day and Sanjay 1/45, which is 3 : 2 in daily output. Since both work every day, the money splits 3 : 2, so Sanjay gets two-fifths of ₹36,000 = ₹14,400. ₹21,600 is Rajan's share, and it is also what you get by splitting in the ratio of the day-counts 30 : 45 — the slower man would then be paid more, which cannot be right. ₹18,000 halves the money, ignoring that Rajan works faster. ₹7,200 is the gap between the two earnings, not Sanjay's own share.