Q. A car averages 55 mph for the first 4 hours of a trip and averages 70 mph for each additional hour. The average speed for the entire trip was 60 mph. How many hours long is the trip?

Option
a) 6
b) 8
c) 11
d) 12
e) 14

• 6 hours...let additional hours be x den total no hours in journey is (4+x)....atq
  ((55*4)+(70*x))/(4+x)=60....=>x=2=>x+4=6 hours
• 11 years agoHelpfull: Yes(30) No(3)
• In 4hr journey = 55*4 = 220mph
  Let in the next additional hour journey = 70*x =70x mph
  So, (220+70x)/(4+x)= 60
  => 220+70x = 240+60x
  => 10x = 20
  => x = 2h
  So the trip is (4+x)=> 6 hours long
• 11 years agoHelpfull: Yes(18) No(0)
• 55*4+70x=60(x+4)
  =>10x=20
  x=2
  total time=4+2=6hrs
• 11 years agoHelpfull: Yes(8) No(0)
• ANS:A
  IN 4 HRS JOURNEY IS=55*4=220M
  IN 2 HRS AFTER FIRST 4 HRS JOURNEY=70*2=140M
  TOTAL JOURNEY=220+140=360M
  AVG SPEED=360/6=60MPH
• 11 years agoHelpfull: Yes(5) No(3)
• average speed is=60
  since in four hours the car travel 5 km/hr less than the avg speed.So it will travel less20 km.and in 70 km/hr speed it make up the 20 km in 2 hrs so.the toatal time will be=4+2=6 hrs
• 11 years agoHelpfull: Yes(2) No(0)
• 55mph for 4 hrs
  70mph for additonal hrs
  55*4+70(x)=240(4+x)
  solving x=2 so total time=6
• 10 years agoHelpfull: Yes(0) No(0)