Answer:
9/40 of his salary
Explanation:
You may want to add the fractions first or subtract one and then the other. I am going to add them first.
(3/8) + (2/5)
(15/40) + (16/40) = (31/40)
1 whole salary (40/40) - (31/40) = (9/40)
Since 9 and 40 have no common factors, the simplified answer is 9/40.