Saturday, September 11, 2010

Speed P6 2010 SA2 RGS P2 Q17

Q17: Jason left Town A at 1 p.m. travelling at 64 km/h towards Town B. Half an hour later, Ben left Town A, travelling at 80 km/h towards Town B. (a) How far ahead was Jason when Ben left Town A? (b) At what time would Ben be 8 km ahead of Jason? [4-mark][Answer given: 32 km, 4.00 pm


64 x 1/2 = 32 km

a) It was 32 km.


8 + 32 = 40 km

80 - 64 = 16 km/h

16 km --> 1 h
40 km --> 40/16 x 1 = 2 1/2 h

         1/2 h                            1 1/2 h
  |--------------|--------------------------------|
1 pm          1.30 pm                                    4 pm

b) It was 4 pm.

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