Question

Plz help me with this math question im preparing for pre board

Answer 1

let its original speed be x..
then distance covered by it =63.
so time taken will be.
= 63/x

if its speed is x+6 then distance is 72.

therefore time taken is 72/x+6.

total time taken =
$\frac{63}{x} + \frac{72}{x + 6} = 3$
$\frac{63x + 378 + 72x}{ {x}^{2} + 6x} = 3$
$135x + 378 = 3 {x}^{2} + 6x$
$3 {x}^{2} - 129x - 378 = 0$


$3( {x}^{2} - 43x - 126) = 0$

${x}^{2} - 43x - 126 = \frac{0}{3}$
${x}^{2} - 43x - 126 = 0$
it's best answer and correct also.