A single slash symbol shows the repeat of either the last crotchet (quarter note), or the last a group of quavers (eighth notes) that make up a beat.
A double slash is used for a group of semiquavers (sixteenth notes).
Similarly, a triple slash is used for demisemiquaver (thirty-second notes) etc.
In the following images, the lower staff shows what is meant by the upper staff.
Slash repeats in simple time:
Slash repeats in compound time:
A percent sign is used to repeat the last bar.
A double slash percent sign centred on a bar line means to repeat the last two bars:
If more than two bars is to be repeated, a percent sign with more slashes can be used.
The odd-one-out is in your first image, where a double slash percent sign is being used for a group of notes that contains mixed durations.