What kind of waves can survive as standing waves?

In a stationary wave,if the distance between a consecutive node and antinode is $5 \ cm$,then find the distance between two consecutive antinodes. (in $cm$)

$A$ stationary wave is represented by $y = 10 \sin \left( \frac{\pi x}{4} \right) \cos (20 \pi t)$,where $x$ and $y$ are in $cm$ and $t$ is in seconds. The distance between two consecutive nodes is (in $cm$)

Standing waves are produced in a string $16 \ m$ long. If there are $9$ nodes between the two fixed ends of the string and the speed of the wave is $32 \ m/s$, what is the frequency of the wave (in $Hz$)?

Two waves of same frequency $n$ are approaching each other with same velocity,$v = 20 \ m/s$ and interfere. The distance between two consecutive nodes is

The distance between the nearest node and antinode in a stationary wave is