Explanation

Given:

The wages of 6 men for 15 days be Rs. 2100

Calculation:

As the wages of 6 men for 15 days be Rs. 2100

The wages of 1 man for 15 days = Rs. 2100/6 = Rs. 350

And, the wages of 1 man for 1 day = Rs.350/15

Now, the wages of 9 men for 12 days = (Rs.350/15) × 9 × 12 = Rs.2520

∴ The wages of 9 men for 12 days is Rs.2520.