v1Measurement, STD2 M7 2021 HSC 25 A rectangular sportsground has been drawn to scale on a 1-cm grid as shown. The scale used is `1:2000`. Johnny took 12 minutes to walk around the perimeter of this sportsground. What was Johnny's average speed in kilometres per hour? (4 marks) --- 8 WORK AREA LINES (style=lined) --- Show Answers Only `3.4 \ text{km/hr}` Show Worked Solution `text{Distance walked on map} \ = \ 2 times (10 + 7) = 34 \ text{cm}`Mean mark 54%. `text{Actual distance}` ` =34 times 2000` `= 68\ 000 \ text{cm}` `=680 \ text{m}` `= 0.68 \ text{km}` `12 \ text{minutes}\ = 12/60 = 0.2 \ text{hours}` `text{Speed}` `= text{distance}/text{time}` `= 0.68/0.2` `= 3.4 \ text{km/hr}`
