Tank? (1 Viewer)

[Lord Ac]

Remember:

1000L tank full...40 mins lata...800L left....how much left after 1 hr.

Two ways, which one???

a) V=Ae^-kt, where: V=?, A=1000, t=60, k= -log (4/5)/40 .... sub in ...

and get: 716


b) if u take it as ....200L lost in 40 mins...yeh? then convert that to hours....so its 300L/hour...so it loses 300 in the first hr...

hence: 700


WTF!!???

Ac

 

[PoLaRbEaR]

the first one is right...in your second answer you're assuming that the rate of depletion is constant, which it is not [its exponential, remember]

 

[howareya]

if you work in out you get 20 hrs something

...

100=1000e^-0.0059t


rearrange and you get your answer...thats easy

 

[babydoll_]

i got 716

 

[sukiyaki]

hey where you ge the first question from? it was in my assessment..

 

[babydoll_]

CSSA trials

 

[Misturi]

lol, l know this isn't in responce to your question but as soon as l saw the topic heading l thought of my maths teacher cuz he's a tank.