I believe that it is too early to begin BMAT preparation, focus on your AS's! Sorry if I get any of these wrong,
15) This question requires really quick but simple mental maths. Average time per section 2 question is about 1 minute so don't spend too much time on questions like these in the actual exam if you have any troubles with them.
In 24 hours, there are 5 X half lives and 3 Y half lives:
24 / 4.8 = 5
24 / 8 = 3
So for X:
Initial = 320
1 HL = 160
2 HL = 80
.......
5 HL = 10
And for Y:
Initial = 480
3 HL = 60
Combined count rate is 10+60=70.
Answer is D.
=============================================================
16) For this question, "=" is the proportional sign (I cannot type it).
According to the question:
x = z^2
y = 1/z^3
Rearrange equations for z:
z = sqroot(x)
z = cbroot(1/y)
sqroot(x) = cbroot(1/y)
x = sqroot(1/y)
x^2 = 1/y
x^3 = 1/y^2
Answer is D.
===============================================================================
9) I have no idea but I would put my bets on F. Check the mark scheme on the BMAT website.
12) Answer is B. I drew a quick sketch of the graph and worked out the answer from there.
71) Answer is A. Using my finger, I traced the path that point D would take according to the sequences.