When you post a picture on social media, it seems like your friends randomly "like" the picture. Independent of the quality or the humor of the photo, there seems to be a 19.3% chance of the picture being "liked" for any given picture.

Let X represent the number of pictures you post until one is "liked." (X represents the photo number that is actually liked.) Find:
$\displaystyle \mu_{{X}}$:

$\displaystyle \sigma_{{X}}$:

$\displaystyle {P}{\left({X}={7}\right)}$:

$\displaystyle {P}{\left({X}<{13}\right)}$:

$\displaystyle {P}{\left({X}>{11}\right)}$:

$\displaystyle {P}{\left({10}\le{X}\le{13}\right)}$: