The task is to generate the correct answer for a given math problem.

Problem: a man spends 2 / 5 of his salary on house rent , 3 / 10 of his salary on food and 1 / 8 of his salary on convenience he has rs . 1400 left with him , find his expenditure on food and conveyance .

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
1000