10分!!Simultaneous Equations

[匿名]

2007-04-07 5:13 am

只求條息
1)Two cars A and B are 45 km apart on a straight road. If they move in opposite directions, they will meet in 1 hour. If they move in the same direction, then the fast car will take 9 hours to catch up with the slow car.Calculate the speeds of each car.

2)If 2 taps are both turned on,they can fill a tank in 12 minutes. If tap A is turned on for 16 minutes and then turned off, it will take tap B another 6 minutes tp fill the tank.How long does it take each tap alone to fill the tank?

回答 (1)

智南

2007-04-07 6:04 am

✔ 最佳答案

1) let the speed of A be x, speed of B be y

x+y= 45 (1)
(x-y)‧9=45 (2)

2) Let the time of A need be x minute, the time of B need be y minute

12‧(1/x + 1/y)=1 (1)
16‧1/x + 6‧1/y=1 (2)

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