the distance between two places A and B is 300 M Rohan starts running from A towards B while Deepak starts running from B towards A. They meet after 4 minutes. Had Rohan doubled his speed and Deepak reduced his by 50%, they would have met one minute earlier. Find their respective speeds.
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Suppose the speed of Rohan and Deepak are x and y m/s. respectively.
When both Rohan and Deepak met after 4 minutes i.e. 60×4 = 240 seconds
Then distance travelled by Rohan = 240x
And distance travelled by Deepak = 240y
And distance between A and B = 300 m
So we have;
240x+240y = 300⇒4x+4y = 5 ...(i)
Now when Rohan doubled his speed i.e. 2x and Deepak reduces his speed by 50% i.e. y2; then they meet 1 minute earlier i.e. 3 minutes i.e. 180 seconds
Distance travelled by Rohan = 180×2x = 360x
And distance travelled by Deepak = 180×y2 = 90y
Then we have;
360x+90y = 300⇒36x+9y = 30 ...(ii)
Now multiplying (i) by 9 and then subtracting (ii) from (i) we get;
36x+36y−36x−9y = 45−30⇒27y = 15⇒y = 15/27 = 5/9
Then form (ii) we have;
36x+9×59 = 30⇒36x+5 = 30⇒36x = 25⇒x = 25/36
Therefore the speed of Rohan is 25/36 m/s and the speed of Deepak is 5/9 m/s
When both Rohan and Deepak met after 4 minutes i.e. 60×4 = 240 seconds
Then distance travelled by Rohan = 240x
And distance travelled by Deepak = 240y
And distance between A and B = 300 m
So we have;
240x+240y = 300⇒4x+4y = 5 ...(i)
Now when Rohan doubled his speed i.e. 2x and Deepak reduces his speed by 50% i.e. y2; then they meet 1 minute earlier i.e. 3 minutes i.e. 180 seconds
Distance travelled by Rohan = 180×2x = 360x
And distance travelled by Deepak = 180×y2 = 90y
Then we have;
360x+90y = 300⇒36x+9y = 30 ...(ii)
Now multiplying (i) by 9 and then subtracting (ii) from (i) we get;
36x+36y−36x−9y = 45−30⇒27y = 15⇒y = 15/27 = 5/9
Then form (ii) we have;
36x+9×59 = 30⇒36x+5 = 30⇒36x = 25⇒x = 25/36
Therefore the speed of Rohan is 25/36 m/s and the speed of Deepak is 5/9 m/s
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Answer will be 41whole 2 by 3m/min as well as 33 whole 1/3 m
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