Explanation:

 Sameer spends 40% of his salary on food articles, and 1/3rd of the remaining on transport. If he saves Rs. 450 per month, which is half of the balance after spending on food items and transport, what is his monthly salary?

Let his total Monthly Salary be 15.

After Spending 40% (i.e 15*40% = 6), He is left with = 15 - 6 = 9.

Now he will spend 1/3rd of the remaining.

1/3 of 9 = 3.

We were left with 9 and now spent 3 out of it.

Amount left in the end (Remaining Amount) = 9 - 3 = 6.

6 --------->  Rs. 900                        (Since Rs.450 is half of the Remaining amount so remaining amount=900) 

1 --------->  Rs. 900/6 = Rs. 150

15 -------> 15 * 150 =  Rs.2250