(Viva Voce) Chap 9 Exercise 9 Question 10

My working:
(a)
Distance covered in 40min = 54km x 40min/60min
= 36km
remaining distance = 120km - 36km
= 84km
remaining time = 2 hour - 40min
= 120 min - 40min
= 80 min
= 1r1r3 hour
average speed for remaining journey = 84km / 1r1r3
= 63km/h

(b) (i) average speed = 120km / 2h 10min
= 120km / 130min
= 12r13 km / min
= 55r5r13 km / h

(ii) average speed = (120km + 120km) / (2h + 2h 10min)
= 240km / 4h 10min
= 240km / 250min
= 0.96km / min
= 5.76km / h

Note: I changed some of the original working as I discovered some errors! These changes are reflected in the working above. For some parts, I did not write down the units as I did not think it was necessary, but added all units in the above working. I also did not elaborate on some parts in the video, but added it in in the above working.

5 comments:

1. This comment has been removed by the author.

2. Presentation [1] - It was abit blurry and i had to squint to try to see what is written on the paper, maybe you could have enlarged~ your handwriting so that it can be easier to read it. :)

Mathematical Terms [1]

Explanation of working/solution must be clear [2]- Voice was slightly muffled

Understanding of concepts [2]

Accuracy of answer [2]

3. Presentation: (1)
The paper was slightly shaking at the start but it became stable after a while. The workings are kind of small and I can't see some of the workings.
Mathematical terms: (1)
Explanation of working: (3)
Understanding of concepts: (2)
Accuracy of answer: (2)

4. Mathemical terms (1)
Explanation of working/solution must be clear (3)
Understanding of concepts (2)
Accuracy of Answer (2)
Presentation (1) EEYER!! Hand writing so small I cannot seeeee.

5. 1. For (a), clear articulation on the approach to take in order to find the answer.

2. Reasons for conversion were articulated, and the steps for conversion is also clearly described.

3. To improve further, perhaps can zoom in to the answer sheet :)

Well done.