A mineral processing plant treats feed whose grade is $0\mathrm{.}91\%$ Zn$.$ The concentrate and tailings are produced from the plant. The grade of the concentrate is $25\mathrm{.}3\%.$ The grade of the tailings is $0\mathrm{.}13\%.$ Estimate:

$($a$)$ Zn recovery in concentrate

$($b$)$ Fed fraction that remains in the concentrate

$($c$)$ Enrichment ratio