Question

A train travels at a certain average speed for a distance of 63 kilometre and then travels at a distance of 72 kilometre at an average speed of 6 kilometre/hour more than its original speed. If it takes 3 hours to complete the total journey, what is the original every speed ?​

Answer 1

Step-by-step explanation:

let S1=x km/hr

d=63

S2=x+6km/hr

d=72

T1+T2=3

63/X+72/X+6 =3

{ 63(X+6)+72x}/X(X+6)=3

63x+378+72x=3x(X+6)

135x+378=3x^2+18x

0=3x^2-117x-378

0=3x^2-126x+9x-378

0=3x(x-42)+9(x-42)

0=(3x+9)(x-42)

since speed cant be negative

X=42