A man spent 2/5 of his salary on food and 1/4 on transport. What fraction of the salary was left?
The fraction spent on food is 2/5 and the fraction spent on transport is 1/4. The total fraction spent is 2/5 + 1/4 = 8/20 + 5/20 = 13/20.
Therefore, the fraction left is 1 - 13/20 = 7/20. Answer: \boxed{\frac{7}{20}}.