variables in shell script is not calculated correctly

What is the mistake in my below shell script:

#!/bin/bash

total=0

for i in 1 2 3 4
do
    echo -n "Enter Passenger Name: "
    read pname
    
    echo -n "Enter Car Number: "
    read ncar

    echo -n "Enter Amount: "
    read amount

    echo -n "Enter Distance Travelled: "
    read dtravelled

    total=$((total + dtravelled))

    average=$(echo "$total 4" | awk '{print $1/$2}')

    if test $dtravelled -gt 10000 -a $dtravelled -le 7000
    then
        bpassenger=$((business_pass + 1))
    elif test $dtravelled -gt 7000 -a $dtravelled -le 5000
    then
        lpassenger=$((leisure_pass + 1))
    else
        opassenger=$((other_pass + 1))
    fi

    if test $i -eq 1
    then
        lname=$pname
        low=$dtravelled
    fi

    if test $dtravelled -lt $low
    then
        lname=$pname
        low=$dtravelled
    fi
    
    echo
done

echo "Total of distance travelled by the开发者_运维百科 passengers: $total"
echo "Average distance travelled by the passengers: $average"
echo "Number of business passengers: $bpassenger"
echo "Number of leisure passengers: $lpassenger"
echo "Number of other passengers: $opassenger"
echo "lowest distance travelled is $low by $lname."

***the below block is not calculated *** I always get empty output on this calculation

if test $dtravelled -gt 10000 -a $dtravelled -le 7000
        then
            bpassenger=$((business_pass + 1))
        elif test $dtravelled -gt 7000 -a $dtravelled -le 5000
        then
            lpassenger=$((leisure_pass + 1))
        else
            opassenger=$((other_pass + 1))
        fi

output:

bash mySript.sh

Enter Passenger Name: ahmad Enter Car Number: 9889 Enter Amount: 20 Enter Distance Travelled: 1100

Enter Passenger Name: sara Enter Car Number: 5214 Enter Amount: 300 Enter Distance Travelled: 1120

Enter Passenger Name: mohammad Enter Car Number: 9713 Enter Amount: 6 Enter Distance Travelled: 500

Enter Passenger Name: nora Enter Car Number: 98765 Enter Amount: 41 Enter Distance Travelled: 7500

Total of distance travelled by the passengers: 10220 Average distance travelled by the passengers: 2555 Number of business passengers: Number of leisure passengers: Number of other passengers: 1 lowest distance travelled is 500 by mohammad.

When writing test $dtravelled -gt 10000 -a $dtravelled -le 7000 in normal mathematical notation, you see that it can never be true:

     dtravelled > 10000   and   dtravelled < 7000
⇔ 10000 < dtravelled < 7000
⇒ 10000 < 7000
⇒ False

Same for the other test with 7000 and 5000.

Adapt you logic. If you run into problems again, add set -x to the beginning of your script or execute it with bash -x scriptFile.sh. This will print the executed statements and variable contents, which will make debugging easier.