1 Maths rate question

劉家慧

2011-05-20 10:55 pm

Gary drives a car at a speed of 80km/h from city Ato city B.At the same time,Louisa and Connie drive at a speed of 60km/h and 65km/h respectively from city B to city A.If Gary meets Louisa 30 minutes after he has met Connie,find the distance between city A and city B.
a.Assume Gary meets Connie after travelling for x hours ,then Gary meets Louisa after travelling for ____ hours.
b.the distance between city A and city B(show your steps):

回答 (1)

用戶2053

2011-05-21 12:11 am

✔ 最佳答案

a)Assume Gary meets Connie after travelling for x hours ,then Gary meets Louisa after travelling for _x hours + 30 minutes = x + 1/2 _ hours.
b)The distance between city A and city B

= The distance of Gary travelling for x hours
+ The distance of Connie travelling for x hours
= (80x + 65x)km

or

= The distance of Gary travelling for x + 1/2 hours
+ The distance of Louisa travelling for x + 1/2 hours
= [80(x + 1/2) + 60(x + 1/2)] km

So80x + 65x = 80(x + 1/2) + 60(x + 1/2)80x + 65x = 80x + 40 + 60x + 305x = 70x = 14The distance between city A and city B= 80(14) + 65(14)= 2030 km

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