Question
In a race of one kilometre, A gives B a start of 100 metres and still wins by 20 seconds. But if A gives B a start of 25 seconds, B wins by 50 metres. The time taken by A to run one kilometre is
Answer: Option A
Answer: (a)Let A take x seconds in covering 1000m and b takes y secondsAccording to the question,x + 20 = $900/1000$ yx + 20 = ${9y}/10$ ...(i)and, $950/1000$ x + 25 = y ...(ii)From equation (i),${10x}/9 + 200/9 = y$${10x}/9 + 200/9 = {950x}/1000 + 25$${10x}/9 + 200/9 = {19x}/20 + 25$${10x}/9 - {19x}/20 = 25 - 200/9$${200x - 171x}/180 = {225 - 200}/9$${29x}/180 = 25/9$$x = 25/9 × 180/29 = 500/29$ seconds.
Was this answer helpful ?
Answer: (a)Let A take x seconds in covering 1000m and b takes y secondsAccording to the question,x + 20 = $900/1000$ yx + 20 = ${9y}/10$ ...(i)and, $950/1000$ x + 25 = y ...(ii)From equation (i),${10x}/9 + 200/9 = y$${10x}/9 + 200/9 = {950x}/1000 + 25$${10x}/9 + 200/9 = {19x}/20 + 25$${10x}/9 - {19x}/20 = 25 - 200/9$${200x - 171x}/180 = {225 - 200}/9$${29x}/180 = 25/9$$x = 25/9 × 180/29 = 500/29$ seconds.
Was this answer helpful ?
More Questions on This Topic :
Latest Videos
Latest Test Papers
Submit Solution