A Train Travels 360 km at a Uniform Speed

Question:

A train travels 360 km at a uniform speed. If the speed had been 5 km/hr more, it would have taken 1 hour less for the same journey. Form the quadratic equation to find the speed of the train.

Solution

Let the speed of the train be

\[ x \text{ km/hr} \]

Then the increased speed is

\[ (x+5)\text{ km/hr} \]

Time taken at speed \(x\):

\[ \frac{360}{x}\text{ hours} \]

Time taken at speed \(x+5\):

\[ \frac{360}{x+5}\text{ hours} \]

Given that the journey would take 1 hour less at the higher speed,

\[ \frac{360}{x}-\frac{360}{x+5}=1 \]

Multiplying both sides by \(x(x+5)\),

\[ 360(x+5)-360x=x(x+5) \]

\[ 1800=x^2+5x \]

Bringing all terms to one side,

\[ x^2+5x-1800=0 \]

Required Quadratic Equation

\[ \boxed{x^2+5x-1800=0} \]

Answer

If \(x\) denotes the speed of the train, then the required quadratic equation is

\[ \boxed{x^2+5x-1800=0} \]

This equation can be solved to find the speed of the train.

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