The total mark is 72. The marks breakdown is as follows:

PS#2
7 Q1(b)
7 Q1(d)
8 Q1(3)
4 Q6
4 Q8(a)
4 Q8(b)
Total: 34

PS#3
6 Q1(1b)
6 Q1(1d)
7 Q1(3)
5 Q3
6 Q5
4 Q7(a)
4 Q7(b)
Total: 38

34+38 is 72


Comments from the markers: 
A LOT had problems with PS#2 Q3 and the corresponding part in
PS#3. Confused on how to deal with the C^2-space. Some treated it as
2-d but neglected to allow complex numbers; some treated it as a 4-d
space but lost track of what they were trying to find and were not sure
how to integrate their results back to complex numbers in 2-d... etc.

A number of the proofs, although the basic idea was there, they failed
to present them well in a logical fashion (A leads to B which leads to C
because of... etc). Instead... a lot were like, "We know that A, B, C...
and since D, E, F... then G is true" when the actual result was
not-so-obvious.

Very surprisingly, many did not realize that if the null space is not
empty then the transformation cannot be 1-1! They used very lengthy
methods to show so.

PS#3 question 3, many neglected to show that their transformation was
linear (in a number of cases they were not)

PS#3 question 5, majority of the proofs were generally quite poor but
attempted nonetheless since it is quite easy to visualize why the result
is so. Many showed that a vector v from V is also in W and claimed V=W,
when all they have shown is that V is a subset of W.

PS#3 question 7, a lot did not understand what the question was asking,
they instead proved that T: R^3 -> R as defined by T(x,y,z) =
(a,b,c)(x,y,z) is a linear transformation.