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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: d0minicz on January 19, 2009, 12:42:16 pm

Title: EASY LINEAR EQUATION QUESTION
Post by: d0minicz on January 19, 2009, 12:42:16 pm: an aircraft fies from its base at an unknown distance, x km away. it travels there and back, averaging 240 km/h for the outward trip and 320 km/h for the return. if the plane was away for 35 mins, find the distance, x km.

sorry ive gone blank :-[ can you please show working out thanks alot
Title: Re: EASY LINEAR EQUATION QUESTION
Post by: ell on January 19, 2009, 01:08:00 pm: $s=\frac{d}{t}$

$\implies t=\frac{d}{s}$

Let $t_{1}$ be the time travelling to destination: $t_{1}=\frac{x}{240}$

Let $t_{2}$ be the time travelling from destination: $t_{2}=\frac{x}{320}$

$t_{1}+t_{2}=35\mbox{ minutes}=\frac{7}{12}\mbox{ hours}$ (ensure all units use hours)

$\frac{x}{240}+\frac{x}{320}=\frac{7}{12}$

$\therefore x=80\mbox{ km}$
Title: Re: EASY LINEAR EQUATION QUESTION
Post by: d0minicz on January 19, 2009, 01:14:24 pm: Couldn't of have made it any more simple, thanks :)