In a race from point A to point B and back, Jack averages 0 miles/hr to point B and 10 miles/hr back to point A.Sandy averages 20 miles/hr in both directions. If Jack and Sandy start race at same time, who’ll finish first ?

• question is wrong
• 6 years agoHelpfull: Yes(1) No(1)
• undefined
  because jack=t=1/0+1/10=undefined because 1/0=not infinity
• 6 years agoHelpfull: Yes(0) No(0)
• 3 answers · Geography
  Best Answer
  They will tie. 30 one way and 10 the other is an average of 20, same as Sandy.
  trea0766 · 1 decade ago
  Comment 1 5
  Answers
  To solve this we can just make a "guess" which will make this a little simpler...we can just "guess" that the distance is 1 mile from X to Y...this way we will be working with easier numbers.
  First Jack
  X->Y
  If the distance is 1 mile and Jack can run for 30 miles in 1 hour we can see that it would take jack 2 minutes to get there [1 mile*(1 hour/30 miles)*(60 minutes/1hour)] = 2 minutes.
  Y->X
  If he can run 10 mph on the way back then it would be [1 mile*(1 hour/10 miles)*(60 minutes/1hour)] = 6 minutes.
  The total time taken it is 8 minutes.
  
  Sandy
  If she can run 20 mph on the way back then it would be [1 mile*(1 hour/20 miles)*(60 minutes/1hour)] = 3 minutes.
  and she does that twice so it takes her 6 minutes.
  
  It takes Jack 8 minutes and it takes Sandy 6 minutes...so Sandy finishes first.
• 6 years agoHelpfull: Yes(0) No(3)