.
The way how the beginner student solves such problems
Let t be the time, in hours, before the trains will meet each other.
At that time, Train A will cover 30*t kilometers;
train B will cover 45*t kilometers.
The distances they cover sum up the whole distance of 300 kilometers.
It gives you an equation
30*t + 45*t = 300 kilometers, or
(30+45)*t = 300,
75t = 300
t = 
= 4 hours.
Then the distance from A is 30*4 = 120 kilometers.
ANSWER. They will meet each other in 4 hours.
Solved.
The way for more advanced students.
Let d be the distance from A (the unknown under the question).
Then the distance from B is 300-d kilometers.
The time spent by A-train is 
hours.
The time spent by B-train is 
hours.
The time is the same, which gives you an equation
= 
.
Multiply both sides by 90.
3d = 2*(300-d), or
3d = 600 - 2d
3d + 2d = 600
5d = 600
d = 
= 120 kilometers.
You got the same answer (!)
Solved.
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See introductory lessons on Travel and Distance problems
- Travel and Distance problems
- Travel and Distance problems for two bodies moving in opposite directions
- Travel and Distance problems for two bodies moving in the same direction (catching up)
in this site.
They are written specially for you.
You will find the solutions of many similar problems there.
Read them and learn once and for all from these lessons on how to solve simple Travel and Distance problems.
Become an expert in this area.
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Hey,
who is a composer/(problems writer) on your side ?
Tell him (or her), by referring to me, that he (or she) does his (or her) job by NOT in a PERFECT mode.
The correct condition must sound in this way:
Points A and B are 300 km apart. A train travels from A to B at 30 km per hour and another train travels
from B to A at 45 km per hour. At what distance from A will both trains meet each other, if they depart simultaneously ?
