QUESTION $3-$ Classification and Performance

A cyclone's performance is being assessed, but the feed is inaccessible and so it is the underflow and overflow streams that are measured. The size distribution of each stream is measured by placing a representative sample into the top of a stack of sieves. The following table gives the mass retained on each of the sieve screens $($i$.$e$.$ the mass is the amount of material larger than the corresponding size and smaller than the size above$).$

$\backslash$table$[[,$Mass on sieve$],[$Sieve size,Underflow,Overflow$],[$microns$,g,g$