An athlete decides to run the same distance in 1/4th less time that she usually took. by how much percent will she have to increase her average speed?

• lets the distance=100 unit.
  1/4th of 100=25unit.
  
  have to increase=(25/(100-25))*100=33.33%
• 13 years agoHelpfull: Yes(31) No(1)
• if u is initial speed and v is final speed.
  t is initial time and 0.75t is final time, then
  u*t= v*(3/4)t
  Then v= 4/3 u
  change in speed = 1/3 u
  % age change = 100*(1/3 u)/u = 33.33 %
• 13 years agoHelpfull: Yes(16) No(3)
• let he takes time t at speed s
  now new time is 3/4t , so speed will become 4/3s
  so speed is 1.33s , that is speed increases by 33.3%
  
• 13 years agoHelpfull: Yes(7) No(1)