Q. Narayan spends 30% of his income on education and 50% of the remaining on food. He gives Rs. 1000 as monthly rent and now has Rs. 1800 left with him. What is his monthly income? 

Explanation by: Sandeep

Narayan's saving and rent = 1000 + 1800 = Rs. 2800
Let his monthly income be Rs. 100
30% of his income he spent on education i.e. Rs. 30
Remaining = 100 - 30 = 70
50% of remaining on food = (70×50)100=Rs. 35

Now, that 35 must be equal to his saving and rent i.e.
35 = 2800 then,
1 = 2800/35

100 = (2800×100)/35=Rs. 8000

So, his income = Rs. 8000