What should be the frequency of beats so that they can be heard clearly in the case of sound?

$A$ tuning fork of known frequency $256\,Hz$ produces $5$ beats per second with the vibrating string of a guitar. The beat frequency decreases to $2$ beats per second when the tension in the guitar string is slightly increased. The frequency of the guitar string before increasing the tension was ..... $Hz$.

$A$ tuning fork of frequency $400 \ Hz$ is in unison with a sonometer wire. The number of beats heard per second,when the tension in the wire is increased by $1 \%$,will be

Two tuning forks $A$ and $B$ produce notes of frequencies $256 \ Hz$ and $262 \ Hz$ respectively. An unknown note sounded at the same time as $A$ produces beats. When the same note is sounded with $B$,the beat frequency is twice as large. The unknown frequency could be ... $Hz$

When a vibrating tuning fork moves towards a wall,why do we hear sound beats?

$A$ set of $14$ tuning forks is arranged in a series of increasing frequencies. Each fork produces '$x$' beats per second with the preceding fork and the last fork is an octave of the first fork. If the seventh fork has the frequency of $114 \text{ Hz}$, the value of $x$ is