Deepu#First#Meridian#95#90
Neethu#Second#Meridian#80#75
Sethu#First#DAV#75#70
Theekshana#Second#DAV#80#79
Teju#First#Sangamithra#88#63
Theekshitha#Second#Sangamithra#91#90

Deepu|First|Meridian|95|90|92.5

$ awk -F'#' ' { if(($4+$5)/2 >90) {print $1 "|" $2 "|" $3 "|" $4 "|" $5 "|" ($4+$5)/2 }} input.txt .

awk -F'#' ' { if(($4+$5)/2 >90) {print $1 "|" $2 "|" $3 "|" $4 "|" $5 "|" ($4+$5)/2 }} input.txt

awk -F'#' ' { if(($4+$5)/2 >90) {print $1 "|" $2 "|" $3 "|" $4 "|" $5 "|" ($4+$5)/2 }}' input.txt

awk -F '#' -v OFS='|' '($4+$5)/2 > 90 { $(NF+1) = ($4+$5)/2; print }' input.txt

awk -F '#' -v OFS='|' '($(NF+1) = ($4+$5)/2) > 90' input.txt