O Levels A Maths Paper 1

• SBS 233 X

  23 Oct 07, 23:05

  Q3. The value, V dollars, of a house is given by V= V(null) e^kt, where V(null) dollars is the original value of the house when built, t is the time in years since it was built and k is a constant. Calculate
  
  (i) the value of k if, after 10 years, the vaule of the hosue has doubled, [3]
  (ii) the vaule of t when the vaule of the house is three times its original value. [2]
  
  Which topic is this under? How to do? Someone explain? Thanks a lot.
• Kohler~*

  24 Oct 07, 09:57

  Originally posted by SBS 233 X:

  Q3. The value, V dollars, of a house is given by V= V(null) e^kt, where V(null) dollars is the original value of the house when built, t is the time in years since it was built and k is a constant. Calculate
  
  (i) the value of k if, after 10 years, the vaule of the hosue has doubled, [3]
  (ii) the vaule of t when the vaule of the house is three times its original value. [2]
  
  Which topic is this under? How to do? Someone explain? Thanks a lot.

  hmm. im not sure is my method correct, but tis is wad i wrote for my paper.
  
  since the value V is doubled, so its 2V
  
  V( null ) is the original price, so when V is doubled, V(null) become V0/2
  
  sub this t=10, v=2v, v0= v0/2 and solve the equation...
  
  anyway, actually i dunno how to do tis question at 1st, so just try my luck lo
• eagle

  24 Oct 07, 10:05

  Originally posted by SBS 233 X:

  Q3. The value, V dollars, of a house is given by V= V(null) e^kt, where V(null) dollars is the original value of the house when built, t is the time in years since it was built and k is a constant. Calculate
  
  (i) the value of k if, after 10 years, the vaule of the hosue has doubled, [3]
  (ii) the vaule of t when the vaule of the house is three times its original value. [2]
  
  Which topic is this under? How to do? Someone explain? Thanks a lot.

  i) { V() e^10k } / { V() e^0} = 2
  Hence, e^10k = 2
  10k = ln2
  k = 0.1 ln 2
  
  ii) { V() e^kt } / { V() e^0 } = 3
  e^kt = 3
  kt = ln 3
  t = 1/k ln3
• tut4nkh4m3n

  24 Oct 07, 10:16

  kt meh? if i rmbred right it's -kt
  
  
• eagle

  24 Oct 07, 10:26

  Originally posted by tut4nkh4m3n:

  kt meh? if i rmbred right it's -kt
  
  

  methodology still the same
• rain-coat

  24 Oct 07, 12:25

  yup for e first part 2V(null)=V(null)blahblahblah
  
  then cancel e V(null) get 2=blahblahblah
  
  then e method same for e 2nd part
• lpx88

  24 Oct 07, 19:29

  This qn i GG
  
  Actually paper 1 i GG coz damn careless