# Biology A-level question

Watch
#1
https://filestore.aqa.org.uk/sample-...3-QP-JUN18.PDF

Question 4.2

I worked out the volume by doing the area of the square x the depth = 0.00025

And I don't know what to do next. Thank you
0
11 months ago
#2
You are right in that the volume of the sample is 0.00025mm^3, giving you a mean of 7 cells/0.00025mm^3.
Since this has been diluted, you next need to find what this would be in the original sample. So if you have 7 cells/0.00025mm^3 in a sample that has been diluted 200 times, what would your original sample be?
This will give you your answer which you need to convert to standard form.
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Current uni students - are you thinking of dropping out of university?

Yes, I'm seriously considering dropping out (132)
14.78%
I'm not sure (40)
4.48%
No, I'm going to stick it out for now (268)
30.01%
I have already dropped out (22)
2.46%
I'm not a current university student (431)
48.26%