Tim and David are 20 km apart. If they walk towards each other,they will meet in 2 hours. If they walk towards the same direction and Tim is behind David. Tim will catch up with David in 5 hours. Find their speeds.
P.S. Let x km/h be the speed of Tim and y km/h be that of David.
applications of simultaneous linear queations
2007-02-18 12:03 am
回答 (1)
2007-02-18 12:24 am
✔ 最佳答案
Let x km/h be the speed of Tim and y km/h be that of David. 2(x+y)=20...............(1)
5y+20=5x...............(2)
咁樣計落去就會搵到答案
解:::::
佢話佢地2個一齊向住對方行,,
2個中會遇見,,
而佢地相融20km,
咁就得出第1條式.
咁佢話tim係david後面,,
咁tim行5個中再+番佢地果20km距離,
就會追到david.
同時間david都行左5個中,
就得到第2條式.
希望幫到你~
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