At a construction site, 2 men and 5 women are paid Rs 2500 for one day's work, while 4 men and 3 women are paid Rs 2900 for a day. Find the daily wage (in Rs) of one woman.

Let a man earn Rs $x$ and a woman Rs $y$ a day. $2x+5y=2500$ and $4x+3y=2900$. Doubling the first: $4x+10y=5000$. Subtracting the second: $7y=2100$, so $y=300$ and $x=500$. Check: $4\times 500+3\times 300=2000+900=2900$. 500 is the man's wage, the classic swap of the two unknowns; 200 is the difference between the two wages; 800 is what one man and one woman earn together.