# student12468

Q.8

## 解答 0

• eric
2019-11-09 23:34:17
First solve 40×2x=40x+100, where x is the walking speed of Eva
• student12468
2019-11-10 11:58:06
can you tell me why
•  eric 2019-11-09 23:34:17
• First solve 40×2x=40x+100, where x is the walking speed of Eva
• eric
2019-11-10 14:22:20
Distance=Speed×Time
•  student12468 2019-11-10 11:58:06
• can you tell me why
• eric
2019-11-10 14:23:39
So after 40s, the distances travelled by Howard and Eva are 40×2x and 40x respectively
• eric
2019-11-10 14:26:55
It takes 40s for Howard to catch up with Eva who is 100m ahead initially
• eric
2019-11-10 14:28:19
So the distance travelled by Howard can also be interpreted as the distance travelled by Eva plus 100m
• eric
2019-11-10 14:29:36
Hence we get the equation 40×2x=40x+100
• eric
2019-11-10 14:31:57
Correction: So after 40s, the distance travelled by Howard can also be interpreted as the distance travelled by Eva plus 100m
•  eric 2019-11-10 14:28:19
• So the distance travelled by Howard can also be interpreted as the distance travelled by Eva plus 100m
• student12468
2019-11-10 16:30:13
ok,thx

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