“Yeah, no problem.”
You're sitting in a coffee shop. Someone who you don't know asks if you will watch over her stuff for her. You say this because you don't mind.
Yeah, no problem.
"No problem" means "yes" or "sure". It is a response that you say to someone who asks you to do something:
A: Could you hold that for me?
B: Sure, no problem.
You can also say "No problem" when someone thanks you for doing something:
B: No problem.
"Yeah" is a more casual way of saying "yes".
Say this to agree with something that a person said:
You can also say "yeah" when you're going to disagree but you want to make your disagreement sound a little softer.
"Yeah" sounds less formal than "yes."