(a) How far has Norman cycled in the first 10 minutes?
Answer: $km [1]$
(b) Norman made two stops along his journey. How long did he stop in total?
Answer: $mins [3]$
(c) How far from Grandmother's house was Norman at 8.40 am?
Answer:
$km [1]$
(d) Calculate the average speed for the entire journey (excluding rest stops).
Answer:
$km / \min [4$

Answer

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Answer

$Average speed = \frac{Total Distance}{Total Time} = \frac{10 - \frac{50}{60}}{80 - 8} = \frac{\frac{50}{60}}{72} = \frac{25}{216}$ km/min

Steps

Step 1 ： $Distance in 10 mins = speed \times time = 10 \times \frac{10}{60} = \frac{100}{60}$ km

Step 2 ： $Total stop time = 5 + 3 = 8$ mins

Step 3 ： $Distance at 8:40 = 10 - \frac{50}{60} = \frac{100}{6} - \frac{50}{60} = \frac{50}{60}$ km

Step 4 ： $Average speed = \frac{Total Distance}{Total Time} = \frac{10 - \frac{50}{60}}{80 - 8} = \frac{\frac{50}{60}}{72} = \frac{25}{216}$ km/min