Is she lying or just a coincidence?

So, I texted two of my friends today asking if we had to go somewhere for school tomorrow. I texted them at the same time, and we all have iPhones. It sent to both of their phones as text messages, and when I texted my other friend who had an iPhone, it sent as iMessage. (text is green, imessage is blue). They didn't reply for about an hour, and they both replied within 5 minutes of each other. One friend claimed she was sleeping, the other didn't say anything. Do you think she was lying when she said she was sleeping and was actually with my other friend? Why does it send as text message rather than iMessage? And what are the odds it'd do the same for both of them then they text me back at practically the same time
47 minutes ago - 4 days left to answer.
Additional Details
No, It doesn't matter that they were hanging out, but it matters if she lies to me about it. She always goes on saying how she hates liars and stuff, and we trust each other with alot, and lately i've felt like she's been the biggest *** so I want others opinions

It seems you already have an opinion of this person. Nothing we can do to change that. We don't know her and can't read her mind.

Sometimes you have to decide if people are really your friend or not.

Might be a coincidence. You can't just call a person liar depending on one vague incident which might not be true. The chances of it being a coincidence are equal right. Of being truthful bothers you so much. I think I should put this behind n watch out in future.cos a liar will get caught atleast at one point. Then.whr. U surely know she's lying or lied… Ud have a valid point to ask them or react.