Fast and furious

Algebra Level 2

The average speed of a car for the first 30 minutes is 120 120 km per hour. In the next 2 hours 30 minutes, it travelled a further 210 210 km. What is the average speed (in km per hour) of the car for the whole journey?


The answer is 90.

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Calvin Lin by Calvin Lin

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5 solutions

Anubhav Singh
Dec 13, 2013

distance covered in first 30 minutes=120/2=60Km and distance covered in next 2.5 hours=210Km so total distance covered in 3 hours=60+210=270Km average speed =distance/time=270Km/3hrs=90 Km/hr

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Fahad Hridoy
Dec 13, 2013

s=vt =120*.5=60 km total distance covered=60+210 km=270 km total time taken=2.5+.5=3 hrs v=s/t=270/3=90 km/hrs

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Chetan Mhetre
Mar 22, 2014

for first 1/2 hr : 120*0.5 = 60kms 60 + 210= 270 kms in 3 hrs avg speed = 270/3 = 90

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Biswajit Das
Mar 22, 2014

1st 30 mins the car cross 120/2=60km 2nd 2h 30 min. it cross=210km total hour =3om+2h30m=3h total distance=210+60=270km average speed=270/3=90km

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Tanzil Hassan
Dec 14, 2013

Average speed= (total distance/ total time)

total distance=(30*120)+210 km

total time=(2.5+.5) hours

Av. Speed=(270/3)= 90 km/h

0 Helpful 0 Interesting 0 Brilliant 0 Confused

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