More on Time & Speed |
Time in MinutesTo convert hours and minutes to minutes, the hours are multiplied by 60 and the minutes added. Example: 6 h 52 m To change minutes to hours and minutes divide by 60 and note
the number left over as minutes. Or, If the answer is taken to one or more decimal places, the
tenths can be multiplied by 60 and rounded, if necessary : for
example, 132/60 = 2.2 hours or 2 h + (0.2 x
60) = 2h + 12 m |
Example: Convert 752 m to hours and minutes: 752 m ÷ 60 = 12.53 h since 12h x 60 = 720 m then 752 m- 720 m = 32m
|
|
Another method: 752 m ÷ 60 = 12.53 h 0.53 x 60 = 31.8 m which rounds to |
Adding and Subtracting TimeTo work with time, calculate hours and minutes separately. Divide hours by 60 to get minutes, either as minutes left over the whole number, or as fractions of an hour. |
Example: Calculate hours and minutes of: 424 m plus 3 h 45 m: First: 424 m / 60 = 7 h 4 m |
Example: What time is it 2 h 55 m earlier than 0820? Calculate hours: 8 h - 2 h = 6 h or 0600 Calculate minutes : 20 m - 55 m= -35 m Subtract the "minus 35" from 0600: 0600 - 0035 m = 0525 |
Working with SpeedTo calculate average speed in one hour of motoring
or sailing: Avg. Speed = [(S1 x min) + (S2 x min) + ...+] ÷ 60, where S1 is the speed in the first period, S2 the speed in the second period and min is the duration at that speed. For example, consider speeds and duration of: 5 knots for 20 minutes , 3 knots for 10 minutes, 6 knots for 30 minutes = [(5 x 20) + (3 x 10) + (6 x 30)] ÷ 60 = [100 + 30 + 180] ÷ 60
|