Archive
9th of March 2017
Mathematics
Q:

two guns were fired from the same place at an interval of 13 minutes but a person in a train approaching the place hears the second report 12mins 30 seconds after the first. find the speed of the train supposing that sound travels at 330 m/s

Junaid Khan - Junior - Class I

Thursday, March 09, 2017 at 17:50:PM

A:

begin mathsize 14px style Distance space traveled space by space train space in space 12 space mins space 30 space sec space straight i. straight e. space in space 750 space seconds
equals 750 straight x comma space where space straight x space is space the space speed space of space the space train space in space straight m divided by straight s

If space the space train space had space not space traveled space this space distance comma space straight a space person space would space have space heard space the space second
shot space only space after space 13 space seconds comma space instead space of space 12 space mins space 30 space sec

Therefore comma space distance space 750 straight x space is space covered space by space sound space in space 30 space secods
rightwards double arrow 750 straight x equals 30 cross times 330
rightwards double arrow straight x equals 13.2 space straight m divided by straight s end style

Thursday, March 09, 2017 at 18:16:PM