Question

the distance between two places A and B is 300m.Rohan starts running from A towards B while Deepak starts running from B to A . They meet after 4 min .Had Rohan doubled his speed and Deepak reduced his by 50% ,they would have met one min earlier .Find their respective speeds.​

Answer 1

Step-by-step explanation:

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 = 2x and

Deepak reduces his speed by 50% = y2;

then they meet 1 minute earlier = 3 minutes( 4 minutes -1 minute) = 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

Hope this helps!!

Answer 2

Step-by-step explanation:

(from the guide) speed of Deepak is 2 km or 33⅓ m/min

speed of Rohan is 2½ km/h or 41⅔ m/mim