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.

Speed 2009 SA1 P2 RGS Q3

3. At 10 am, Andy drove from Town A to Town B at an average speed of 100 km/h. At the same time, Jeremy drove from Town B towards Town A at an average speed of 95 km/h. They met at 12.30 pm. Find the distance between Town A and Town B.

          2 h           1/2 h

   !--------------!-------------!

10 am        12 pm      12.30 pm 

100 + 95 = 195 km/h

195 x 5/2 = 487.5 km