Math, asked by meghanavm271102, 1 month ago

A train travels a distance of 300 km at constant speed of
the train is by increased by 5km an hour, the journey
would have taken 2 hours less. Find the original speed of the train

Answers

Answered by parthinaparthiban
2

Answer:

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Attachments:
Answered by ItzBrainlyLords
12

 \large  \star \:  \: \underline{ \underline{ \red{  \tt{given : }}}}

 \\  \large \tt \:  \:  \:  \:  \:  \:  \:  \rightarrow \: distance = 300km \\  \\  \large \tt \:  \:  \:  \:  \:  \rightarrow \: increased \:  \: speed = 5km\\  \\  \large \tt \:  \:  \:  \:  \:  \:  \:  \rightarrow \: time = 2hr \:  \: less \\  \\

 \large \tt \bull \: let \:  \: constant \:  \: speed \:  \: of \:  \: train \\ \large \:  \:  \:  \tt \:  \:   = \green{ x \:  \: km /  hr} \\  \\

 \large \tt:  \implies time \:  \: tken \:  \: to  \: \: cover \:  \: 300km \\  \\  \large \tt \:  \:  \:  \:   =  \frac{300}{x} hrs \\  \\

 \large \tt:  \rightarrow \: seed \:  \: increased \:  \: by \:  \: 5km/h \\  \\  \large \tt \:  \:  \:  \:   =  \frac{300}{x + 5} hrs \\  \\

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 \:

➪ It is given that the time to cover 300km is reduced by 2 hours

 \\  \large \tt \therefore \:  \:  \frac{300}{x}  -  \frac{300}{x + 5}  = 2 \\  \\

 \large  :  \implies \tt \dfrac{300(x + 5) - 300x}{x(x + 5)}  = 2 \\ \\   \\  \large  :  \implies \tt 2 {x}^{2}  + 10x  = 1500 \\  \\ \large  :  \implies \tt  {x}^{2}    + 5x - 750= 0 \\  \\  \large \rm  \underline{\underline{splitting \:  \: the \:  \: middle \:  \: term : }} \\  \\  \large  :  \implies \tt  {x}^{2}      + 30x  - 25x - 750= 0 \\  \\  \large  :  \implies \tt  (x + 3)(x - 25) =  0 \\  \\

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 \large  \boxed{\rm \therefore \underline{ \:x = 25 \:  \: or \:  \: x =  - 30}} \\

Since, x cannot be negative

  • therefore, x = 25km/h

Hence,

  • Original speed of train = 25km/h

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