Question Number 218312 by Rojarani last updated on 06/Apr/25
Answered by mr W last updated on 07/Apr/25
$${say}\:{the}\:{time}\:{needed}\:{from}\:{house}\:{to}\: \\ $$$${station}\:{A}\:{is}\:{x},\:{and}\:{from}\:{house}\:{to} \\ $$$${station}\:{B}\:{is}\:{y}. \\ $$$${for}\:{up}\:{train}\:{it}\:{is}\:{given}: \\ $$$${x}+\mathrm{4}={y}+\mathrm{1}\:\Rightarrow{y}={x}+\mathrm{3} \\ $$$${for}\:{down}\:{train}: \\ $$$${say}\:{i}\:{shall}\:{start}\:{z}\:{minutes}\:{earlier} \\ $$$${to}\:{catch}\:{the}\:{train}\:{at}\:{B},\:{then} \\ $$$${x}+{z}={y}+\mathrm{4} \\ $$$${x}+{z}={x}+\mathrm{3}+\mathrm{4} \\ $$$$\Rightarrow{z}=\mathrm{7}\:{minutes} \\ $$