Calculations

 To calculate the time difference between 10:04 and 18:58 on a calculator, follow these steps:

1. Convert the times to minutes:

   • For 10:04, convert the hours and minutes to minutes:
     $10\times 60+4=604$ minutes.
   • For 18:58, convert the hours and minutes to minutes:
     $18\times 60+58=1138$ minutes.

2. Subtract the two times in minutes:

   • $1138-604=534$ minutes.

3. Convert the result back to hours and minutes:

   • To convert 534 minutes to hours and minutes:
     • Divide 534 by 60:
       $534÷60=8$ hours (the whole number part).
     • Multiply 8 hours by 60 to get the minutes:
       $8\times 60=480$.
     • Subtract 480 from 534 to get the remaining minutes:
       $534-480=54$ minutes.

Thus, the time difference is 8 hours and 54 minutes.

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Congestion Percentage:

• The congestion level is expressed as a percentage increase in time compared to free-flow traffic.
• Formula:$$\text{Congestion Level (\%)}=\left(\frac{\text{Rush Hour Travel Time}-\text{Free-Flow Travel Time}}{\text{Free-Flow Travel Time}}\right)\times 100$$
• Example: If a free-flow journey takes 30 minutes but takes 50 minutes during rush hour:$$\left(\frac{50-30}{30}\right)\times 100=66\mathrm{\%}$$