[QUOTE=shilpakokkanti;1586354]1)In a race of 500 m,L beats M by40 sec and beats N by 12 5mm.If M and N run a 500m race,M beats N by 40 sec.Find the time taken by M to run the race?
280 is the ans.
Also find the speed of N??
ans is 1.5625 m/s.
Similar to one u posted earlier...
let t be the time taken(in seconds) by L to complete the race
=>time taken by M = t+40 and time taken by N to complete the race = t+40+40 = t+80 sec
since L beats N by 125 m
t*500/t - t*500/(t+80) = 125 => 375 =500t/(t + 80)
15 (t+80) = 20t => 5t = 15*80 => t = 240 sec
=> time taken by M to complete the race = t + 40 =240 + 40 =280 sec
spedd of N = 500/(240 +80) = 500/320 = 25/16 = 1.5625 m/s