A train travels at a certain average speed of a distance of 54km and than travels a distance of 63km at an average speed of 6 km/h more than the first speed.if it takes 3 hours to complete the total journey what is its first speed?
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let the speed be x
according to question
(54/x)+(63/x+6)=3
on solving this we will get this equation :
3x²-99x-324=0
x²-33x-108=0
x²-36x+3x-108=0
x(x-36)+3(x-36)=0
(x+3)(x-36)=0
x=36 or x=-3(rejected)
first speed of the train is 36km/h
according to question
(54/x)+(63/x+6)=3
on solving this we will get this equation :
3x²-99x-324=0
x²-33x-108=0
x²-36x+3x-108=0
x(x-36)+3(x-36)=0
(x+3)(x-36)=0
x=36 or x=-3(rejected)
first speed of the train is 36km/h
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