Amey B.

asked • 02/13/16

time speed distance

peter can cover a certain distance in 1 hr 24 min by covering two third of the distance at 4 kmph and the rest at 5 kmph find the total distance
 
let distance x
2/3x+ 1/3x =7/5
   4        5   
 
how that 7/5 come from please explain

1 Expert Answer

By:

Arthur D. answered • 02/13/16

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1 hour and 24 minutes is 1 and 24/60 hours which equals 1 2/5 which is 7/5
 
(2x/3)/4+(x/3)/5=7/5
multiply both sides by 60
15(2x/3)+12(x/3)=12(7)
10x+4x=84
14x=84
x=84/14
x=6 km
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Amey B.

i also have one doubt that if we assume x as distance why multiplied x with 2/3 and 1/3
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02/14/16

Arthur D.

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distance=rate*time
time=distance/rate
the problem states " 2/3 of the distance at 4 kph and 1/3 of the distance at 5 kph "
if x=distance than you have (2/3)(x) or 2x/3 and (1/3)(x) or x/3
then the distances are divide by the rates 4 and 5
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02/14/16

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