Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    6
    ReputationRep:
    Hi,

    This is for my biology practice paper, and I may work this out myself in due time, but I'm sat here trying to workout this maths question on it. I have the answer in-front of me - but I cannot see how you get to this figure. Can someone explain it to me?

    Doctors investigated the accuracy of two methods, A and B, used to measure sperm counts.They obtained samples of semen from 500 men. They used both methods to obtain a spermcount for each sample.
    • Method A required the semen to be diluted by a factor of 2 before counting.• Method B required dilution by a factor of 20.


    Method B involved counting the number of sperm cells seen in small squares on aspecial glass microscope slide. Each square contained 0.25 × 10^–6 cm3 semen. Forone diluted sample of semen, the mean number of sperm cells per square was 1.05.Calculate the mean number of sperm cells per cm3 of semen. Show your working

    Probably won't get a question like this on my exam paper - but I would feel the better for having a firmer understanding on the working-out.
    • Thread Starter
    Offline

    6
    ReputationRep:
    It's okay - I worked it out.

    Divide - 1/0.25 × 10^–6 cm3 ...x 20. Then x 1.05. = 84 x 10^6.

    It's because I hadn't figured out the first division.

    It's a shame I wouldn't get 20-mins in an exam to get my head around this...but then again, it is 7am. (need more coffee, perhaps).
 
 
 
  • See more of what you like on The Student Room

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

  • Poll
    Would you like to hibernate through the winter months?
    Useful resources

    Make your revision easier

    Maths

    Maths Forum posting guidelines

    Not sure where to post? Read the updated guidelines here

    Equations

    How to use LaTex

    Writing equations the easy way

    Student revising

    Study habits of A* students

    Top tips from students who have already aced their exams

    Study Planner

    Create your own Study Planner

    Never miss a deadline again

    Polling station sign

    Thinking about a maths degree?

    Chat with other maths applicants

    Can you help? Study help unanswered threads

    Groups associated with this forum:

    View associated groups
  • See more of what you like on The Student Room

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

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.