Question

a train travels at a certain average speed for distance of 63km and then travels at a distance of 72km at an average speed of 6km/hr more than its original speed. if it takes 3hours to complete total jorney , what is the original speed?

Answer 1

↑ Here is your answer ↓
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Let original speed of the train be 'x' km/h

$Time = \frac{Distance}{Speed}$

$\frac{63}{x} + \frac{72}{x + 6} = 3$

$\frac{63(x+6) + 72x}{x^2 + 6x} = 3$

$\frac{63x + 378 + 72x}{x^2 + 6x} = 3$

$\frac{135x+378}{x^2 + 6} = 3$

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

$3x^2 + 18x - 135x - 378 = 0$

$3x^2 - 117x - 378 = 0$

Dive throughout by 3,

$x^2 - 39x - 126 = 0$

By solving the quadratic equation, you get

$x = 42 km/h$

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Glad to help you.
@EmadAhamed

Answer 2

Answer is attached.

Here's is Answer key for whole maths Leaked board paper 2018 =>
brainly.in/question/3121329