a truck covers a distance of 150km at a certain average speed and then covers another 200km at an average speed which is 20 km per hour more than the first speed. if the truck covers the total distance in 5 hours, find the first speed of the truck.
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d1=150km
s1=x km/hr
t1=150/x hr
d2=200km
s2=20+x km/hr
t2=200/(20+x)hr
ATQ:
150/x+200/20+x=5
(3000+150x+200x)/x2+20x=5
3000+350x=100x+5x2
3000+250x=5x2
5x2-250x-3000=0
x2-50x-600=0
a=1
b=-50
c=-600
=(50+70)/2
=60 km/hr
=(50-70)/2
=-10 km/hr
Since a negatine can't be the value of speed, the speed of the truck calculated is 60 km/hr.
s1=x km/hr
t1=150/x hr
d2=200km
s2=20+x km/hr
t2=200/(20+x)hr
ATQ:
150/x+200/20+x=5
(3000+150x+200x)/x2+20x=5
3000+350x=100x+5x2
3000+250x=5x2
5x2-250x-3000=0
x2-50x-600=0
a=1
b=-50
c=-600
=(50+70)/2
=60 km/hr
=(50-70)/2
=-10 km/hr
Since a negatine can't be the value of speed, the speed of the truck calculated is 60 km/hr.
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