A passenger and a freight train start toward each other at the same time from two points 300 kilometres apart. If the rate of the passenger train exceeds the rate of the freight train by 15 km/h, and they meet after 4 hours, what must the rate of each be?

해법

A p a sse n g er an d a f re i g h t t r ain s t a r t t o w a r d e a c h o t h er a t t h e s am e t im e f ro m tw o p o in t s 300 ki l o m e t res a p a r t . I f t h e r a t e o f t h e p a sse n g er t r ain e x cee d s t h e r a t e o f t h e f re i g h t t r ain b y 15 km / h, an d t h ey m ee t a f t er 4 h o u rs, w ha t m u s t t h e r a t e o f e a c h b e ?

passenger trai n^{'} s speed : 45

freight trai n^{'} s speed : 30

솔루션 단계

Translate the problem into an equation:

x \cdot 4 + (x - 15) \cdot 4 = 300

x

해결 대상

, x \cdot 4 + (x - 15) \cdot 4 = 300 : x = 45

speed 찾다

passenger trai n^{'} s speed : 45

freight trai n^{'} s speed : 30