Linear Equations in Two Variables question :)
Please help :)

Question

Linear Equations in Two Variables question :)
Please help :)

hba · Answer

Well there are a few methods we can use,

1)Breaking the middle term

2)Completing the whole square

3)Quad formula.

hba · Answer

Do you have a particular question i can help you on ?

theviper · Answer

A motorboat whose speed is $\large{18km/hr}$ in still takes one hour more to go $24km$ upstream than to return downstream the same spot. Find the speed of the stream.

shubhamsrg · Answer

Did you form your equations ?

theviper · Answer

that is the problem :D

theviper · Answer

i know how to solve them but can't make those equations :(

shubhamsrg · Answer

Leme try :
Let speed of stream be x
distance = 24
for upstream, speed = 18-x
for downstream , speed = 18+x

If time taken to go downstream is t, then it says time taken to go upstream is (t-1)

Use distance = speed/time to get your 2 eqns.
hope this helps ?

shubhamsrg · Answer

Am sorry, if t is for downstream, then (t+1) is for upstream*

theviper · Answer

$$\LARGE{\dfrac{24}{18-x}=t+1}\quad\quad\quad..............(eq.i)$$
$$\LARGE{\dfrac{24}{18+x}=t-1}\quad\quad\quad..............(eq.ii)$$
????????

theviper · Answer

Am i right @hartnn ??

hartnn · Answer

those are correct equations.

theviper · Answer

thanx everyone :)

hartnn · Answer

wait, why is there t+1 ? 
what have you considered 't' as ?

theviper · Answer

time

hartnn · Answer

t= downstream time ??
or t= upstream time ?

theviper · Answer

oh wait @shubhamsrg is wrong i think :/

theviper · Answer

he took t+1 as upstream time & t-1 as downstream instead of taking t as downstream time & t+1 as upstream time :)

hartnn · Answer

no...he didn't take t+1 as upstream time & t-1 as downstream...
he said "$ \large If$ time taken to go downstream is t, then it says time taken to go upstream is (t-1)"
actually its t+1.

hartnn · Answer

as you said....so what are your modified equations ?

theviper · Answer

$$\LARGE{\dfrac{24}{18-x}=t-1}\quad\quad\quad..............(eq.i)$$$$\LARGE{\dfrac{24}{18+x}=t}\quad\quad\quad..............(eq.ii)$$

hartnn · Answer

if downstream = t,
upstream =  t+1 .

theviper · Answer

oh yes sorry :)

shubhamsrg · Answer

I had corrected myself after that!  :|

theviper · Answer

yess:/