plzzzzz

[enthada]

There is a 50m long army platoon marching ahead. The last person in the platoon wants to give a letter to the first person leading the platoon. So while the platoon is marching he runs ahead,reaches the first person and hands over the letter to him and without stopping he runs and comes back to his original position. In the mean time the whole platoon has moved ahead by 50m.

The question is how much distance did the last person cover in that time. Assuming that he ran the whole distance with uniform speed.

[shammydodger]

I make it 100m. If the platoon has moved a total of 50m, then on his forward run, he will have run the 50m length of the platoon, plus half the distance that the platoon moves (25m), making 75m on the forward journey. On the return journey, he needs to cover the 50m of the platoon, but the platoon moves forward by another 25m, so he actually covers just 25m on the ground, making 100m in total.

Then again, I did only manage grade B in GCE maths, so I may be mistaken.

[mjd]

Hi, I haven't an answer myself yet but I don't think that the above can be correct. The assumption is that the platoon marches 25m while the guy is running forward and 25m when he is running back again. Now the time taken to run out must be longer than the time to run back (he's got further to go) so the platoon must march further during the first half.

[shammydodger]

mjd

Put like that, I agree with you and the distance must therefore be greater than 100m.

[prettystuck]

120.72 m.