QUANTITATIVE MODELLING (DSC1520)
MAY/JUNE 2019
POSSIBLE SOLUTIONS
OPTION [3]
The equation of C as a function of Q can be written as 𝑪 = 𝒎𝑸 + 𝒃 where 𝑚 = slope and 𝑏 is
the vertical intercept (or y-)
Points on the graph is written in the form (𝑄1; 𝐶1), (𝑄2; 𝐶2) and so on.
The given points are therefore (𝑄1; 𝐶1) = (10; 40) and (𝑄2; 𝐶2) = (20; 70)
The slope 𝑚 is given by 𝒎 = C 2 – C1/Q2 – Q1 = 70 - 40/ 20 - 10 = 30/10 =3
Now C = 3Q + b
Using the points (10; 40)
40 = 3(10) + b
40 = 30 + b
40 – 30 = b
10 = b
C = 3Q + 10
C = 3(35) + 10
C = R115
Page 1 of 16
MAY/JUNE 2019
POSSIBLE SOLUTIONS
OPTION [3]
The equation of C as a function of Q can be written as 𝑪 = 𝒎𝑸 + 𝒃 where 𝑚 = slope and 𝑏 is
the vertical intercept (or y-)
Points on the graph is written in the form (𝑄1; 𝐶1), (𝑄2; 𝐶2) and so on.
The given points are therefore (𝑄1; 𝐶1) = (10; 40) and (𝑄2; 𝐶2) = (20; 70)
The slope 𝑚 is given by 𝒎 = C 2 – C1/Q2 – Q1 = 70 - 40/ 20 - 10 = 30/10 =3
Now C = 3Q + b
Using the points (10; 40)
40 = 3(10) + b
40 = 30 + b
40 – 30 = b
10 = b
C = 3Q + 10
C = 3(35) + 10
C = R115
Page 1 of 16
