Answer:
15
Explanation:
The LCD for 1/5 and 1/3 is 15 due to 5, 10, 15
3, 6, 9, 12, 15
15 is the first number that they have in common, when using their denominators, maybe next time with this explanation you won't need help here.
If it was 1/3 and 1/6, you would go 3, 6 and then 6 (though teachers want you to put more to show you understand then put ... at the end since its infinite) So hopefully that clears it up for you.