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20. Two trains running in opposite directionscross a man standing on the platform in54s and 34s respectively and they crosseach other in 46 s. Find the ratio of theirspeeds.(a) 3:2 (b) 2:3 (c) 5:3 (d) 3:5 |
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Answer» b is a right answer is yes to cross a man train should cross it's own length.coming from opposite direction so both speed will add.also to cross each other total dis=both train length let speed of trains are x m/sec & y m/sec their length are a & btime= dist/speedt1= a/x=54----(1)a=54xb/y= 34----(2)b= 34ya+b/x+y=3654x+34y/x+y=3654x+34y=36x+36y54x-36x= 36y-34y18x=2yx/y= 2/18=1/9x : y = 1: 9 b is the right answer Let the speeds of the two trains bexm/sec and y m/sec respectively.Then, length of the first train = 54xmetres,and length of the second train = 34ymetres54x+34y÷x+y=4654x+ 34y= 46x+46y54x+ 34y= 46x+ 46y8x= 12yx÷y=3÷2therefore a. is the correct answer 3:2 is a right answer 💖✍️🌎🇨🇮👍🙏👈👌 |
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