Question

A train travels 480 km at a uniform speed. If the speed had been 10km/h more, it

would have taken 4 hours less for the same journey, find the speed of the train?​

Answer 1

$\huge \sf \pink{answer}$

40 km ph

$\huge \sf \pink{given}$

$\implies$train travels 480 km

$\implies$speed had been 10km/h

$\huge \sf \pink{find}$

$\implies$speed of the train

$\huge \sf \pink{formula \: used}$

$\implies$Speed is Distance/Time

$\huge \sf \pink {solution}$

$\implies$Distance travelled by the train = 480 km

$\implies$Let the speed of the train be x kmph

$\implies$Time taken for the journey = 480/x

$\implies$Given speed is decreased by 8 kmph

$\implies$Hence the new speed of train = (x – 8) kmph

$\implies$Time taken for the journey = 480/(x – 8)

$\implies$480/(x – 8) – 480/x = 3

$\implies$480(x – x + 8)/x (x-8) = 3

$\implies$480/3 * 8 = x2 -8x

$\implies$1280 = x2 – 8x

$\implies$x2 – 8x – 1280 = 0

$\implies$On solving we get x = 40

$\implies$Thus the speed of train is 40 kmph

Answer 2

Answer:

⟹ train travels 480 km

⟹ speed had been 10km/h

\huge \sf \pink{find}find

⟹ speed of the train

\huge \sf \pink{formula \: used}formulaused

⟹ Speed is Distance/Time

\huge \sf \pink {solution}solution

⟹ Distance travelled by the train = 480 km

⟹ Let the speed of the train be x kmph

⟹ Time taken for the journey = 480/x

⟹ Given speed is decreased by 8 kmph

⟹ Hence the new speed of train = (x – 8) kmph

⟹ Time taken for the journey = 480/(x – 8)

⟹ 480/(x – 8) – 480/x = 3

⟹ 480(x – x + 8)/x (x-8) = 3

⟹ 480/3 * 8 = x2 -8x

⟹ 1280 = x2 – 8x

⟹ x2 – 8x – 1280 = 0

⟹ On solving we get x = 40

⟹ Thus the speed of train is 40 kmph