Question

A man spends 4/5 of his monthly income on house rent, 1/2 on food and 1/5 on other items. He saves Rs. 400 in the end. What was his monthly income?

Answer 1

Something is wrong with the given question. Any how I will try to find a better answer.

Let x be the man's income
Then his expenditure on house rent =4x/5
His expenditure on food =x/2
His expenditure on others =x/5

Therefore the expression on his expenditure
= 4x/5 + x/2 + x/5 + 400 = x
= 4x/5 + x/2 + x/5 - x = - 400
= (8x + 5x + 2x - 10x) / 10 = - 400
= 5x = - 4000
= x = - 800
Therefore his income = - 800 Rs ( this may not make sense so let me assume in different way)

Let 400 be the money he borrowed to fulfill his expenditures
Then our equation will be
= 4x/5 + x/2 + x/5 - 400 = x
= 4x/5 + x/2 + x/5 - x = 400
= (8x + 5x + 2x + 10x) / 10 = 400
= 5x = 4000
= x = 800
Therefore, his income in one month = 800 ( if we assume that he borrowed 400 instead of saving)

Sorry if I did any thing wrong......