Wednesday, September 15, 2010

Speed P6

At 0954 Mary left Everton Park and cycled towards Serene Park while Joy left Serene Park and cycled towards Everton Park. At 1004, the two cyclists passed each other. 5 minutes later, Mary reached Serene Park but Joy was 780 m from Everton Park.

(a) At what speed were the two cyclists approaching each other?
(b) Find the distance (in km) between Everton Parkf and Serene Park.


TM1 : TM2 = 10 : 5 = 2 : 1  DM1 : DM2 = 20 : 10
JM1 : JM2 = 10 : 5 = 2 : 1   DJ1 : DJ2 = 2 : 1 = 10 : 5

                                                                 (DM2 = DJ1)
DM1 - DJ2 = 20 - 5 = 15 u --> 780 m
M [][][][][][][][][][][][][][][][][][][][][][][][][][][][][][]
J  [][][][][][][][][][][][][][][] [][][][][][][][][][][][][][][]
   |<-------- 780 m ------->|

15 u --> 780
1 u --> 780/15 = 52

30 u --> 30 x 52 = 1560 m
                          = 1.56 km

1560/10 = 156 m/min

a) It was 156 m/ min.         Approaching speed (Combined speed)

b) It was 1.56 km.

No comments:

Post a Comment