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Difficulty: HardTime Measurements and Calculations

A surveillance drone has a maximum flight endurance of 345 minutes before its battery is completely depleted. If the drone is launched at 21:40 for a continuous mission, at what time will the drone's battery be completely depleted?

  1. A
    01:25
  2. B
    03:15
  3. 03:25Answer
  4. D
    03:55

Answer

03:25
To find the completion time, you must add the total duration to the start time. First, convert 345 minutes into hours and minutes by dividing by 60, which gives 5 hours with a remainder of 45 minutes. Next, add 5 hours and 45 minutes to the launch time of 21:40. Adding the hours gives 26:40. Adding the 45 minutes gives 26:85. Since 85 minutes is equivalent to 1 hour and 25 minutes, this shifts the time to 27:25. Finally, subtract 24:00 to account for crossing midnight, resulting in the correct time of 03:25.

Step-by-Step Solution

1
Convert the total flight duration from minutes to hours and minutes.
345 minutes ÷ 60 = 5 hours with a remainder of 45 minutes.
Converting to hours and minutes makes it easier to add to the given start time.
2
Add the flight hours to the launch time.
21:40 + 5 hours = 26:40.
This finds the hour of completion before adjusting for the 24-hour clock.
3
Add the remaining flight minutes to the result from Step 2.
26:40 + 45 minutes = 26:85.
This incorporates the remaining minutes of the flight time.
4
Format the resulting time into a standard 24-hour clock format.
26:85 becomes 27:25 (since 85 minutes is 1 hour and 25 minutes). 27:25 on a 24-hour clock is calculated as 27:25 - 24:00 = 03:25.
Time must be expressed in a standard 24-hour format, properly accounting for crossing midnight (24:00).

Key Concept

Converting minutes into hours and minutes, and accurately adding elapsed time across the midnight boundary on a 24-hour clock.
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Topics

Time Measurements and Calculations

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