Thursday, June 3, 2010

Speed P6

A Van left Port Penang for Town Lalu at 9 a.m. A Car started its journey along the same route as the Van from starting point, two hours later. The car overtook the Van at 3 p.m. The speed of the Car was 30 km/h faster than the Van. The Van took 7 hours to reach Town Lalu. Find the distance between Port Penang and Town Lalu.

         3 h           3 h
   !----------!-----------!
9 am      12 noon       3 am

6 - 2 = 4 h

30 x 4 = 120 km         Additional distance travelled by Car
                                 to catch up with Van in 4 h
                                 = Distance travelled by Van in the first 2 h

120 ÷ 2 = 60 km/h     Speed of van

60 x 7 = 420 km

The distance between Port Penang and Town Lalu was 420 km.

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