simple question about sample randomness

#1
Thanks for looking at this.

I've been given a sample of data of 105 cars. Our teacher didn't specify whether or not the sample is random, but most of the hypothesis tests I'm to perform require a random sample. I thought I could get around the possible non-randomness of the sample by taking a simple random sample of 50 of the 105 cars. Would that fulfill the random sample requirement?

I've tried looking on the internet for an answer but I usually just get definitions of random sample and why they're better than non-random samples.

Thank you!