NNT, two Dose Regimen questions (using external resource) and 'infusion-related' Q.

Question 32) I've done NNT questions a lot and know the method for them (and always got them right). However, for this question in a formative exam, my teacher marked it as 21, however I got 19! I've shown my calculations in the picture and I definitely need to know: did she just get it wrong?

Question 2) Same with this one here. The answer is supposedly 26.4ml, yet I got 26.2ml. See the relevant pics attached.

Question 7) Again, I've showed my calculations and the answer is 4.3mg, yet I got 2.2mg. I've attempted other questions like this and never got them wrong, so... yep. See relevant pics attached.

Question 9) I actually have never came across this type of question before. The answer is 7.5ml. I've showed my calculations in the picture; what is the next step I am missing? Would love to see a quickfire method to answer this, given the information provided. I know how to calculate infusion rates in mL/hour and drops/min EASILY, but in this question, the rate is already given (0.1ml/hr). Hmm...

I appreciate the support guys; I have a calcs exam on w/c 10th July and looking forward to smash it. I've practised a LOT of questions and am pretty confident, but it's just these questions above that have me stumped now. Once I've cleared these, could anyone provide me with some Yr 4 Pharmaceutical Calculations Practice Papers (40 Questions in total, 8 Questions require an external resource pack)? I cannot find any online or on YT (great for practising individual questions though) and I would love to just run through a whole paper, to see how I am for time (2hrs given in the exam).

P.S. Apologies if some appear rotated the wrong way - no idea why TSR did that for some images, even though I had taken them in portrait and in Gallery, the orientation is normal.