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Can anyone check this math please (urgent) [pictures inside]

  1. Oct 25, 2014 #1
    Mod note: Moved from a technical math section, so this post doesn't contain the homework template.
    It seems I can't solve 4th grade questions any more, I'm confused with division vs. subtraction in fractions.

    Is the solution for question 1 and 2 correct?

    IMG_3821.JPG





    IMG_3822.JPG

    Disregard the solution for question 3 and 4 in the second picture. The solutions I came up with for them are:

    Q3. 12x4=48


    Eggs that were broken= 48x1/8= 6

    48-6=42
    No. of eggs remaining= 42x3/7= 18

    Q4.

    3/4-1/8= 5/8

    5/8-1/8= 1/2

    Is this correct? TIA!
     
    Last edited by a moderator: Oct 25, 2014
  2. jcsd
  3. Oct 25, 2014 #2

    Mark44

    Staff: Mentor

    We discourage members from posting images of their work, primarily because we as helpers can't go into the work and point out where errors are present. We also discourage posts that contain too many questions (with "too many" not precisely defined).

    1 is correct.
    2 is way off. Subtraction is NOT the operation to use. Any time a problem says "x/xx of ..." the implied operation is multiplication.
    3 is correct.
    4 is correct.

    It's easy enough to check your work - you don't have to rely on us to confirm your answers. Just substitute the numbers you found into the problem, and verify that they work.
     
  4. Oct 26, 2014 #3
    Thanks for your reply, I'll keep that in mind from now on.

    For Q2. 5/6x3/5= ans is this correct?

    Just need to confirm.

    Thanks again!
     
  5. Oct 26, 2014 #4
    Or is it 5/6x3/5= 1/2

    And then

    5/6-1/2= No of boys with A grade?
     
  6. Oct 26, 2014 #5

    Mark44

    Staff: Mentor

    Yes

    Sort of, but I wouldn't have done it this way. Also, this is not the number of boys, which can't possibly be a fraction. Of the kids who received an A, what fraction of them have to be boys?
     
  7. Oct 27, 2014 #6

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    I don't see how you can answer (2). There is not enough information!

    Suppose the class has 30 students. (5/6)(30)= 25 scored an "A". 3/5 of those, (3/5)(25)= 15, were girls so 25- 15= 10 of those who scored an "A" were boys. But we cannot say "what fraction" that is because we don't know how the other 30- 25= 5 students are divided between boys and girls.

    Perhaps they were all boys: Perhaps the class consisted or 15 girls and 15 boys. All 15 girls and 10 of the boys scored an "A". 10/15= 2/3 of the boys scored an "A".

    Or perhaps they were all girls. Perhaps the class consisted of 20 girls and 10 boys. 15 of the girls and all 10 of the boys scored an "A". 10/10 of the boys scored an "A".

    Both of those scenarios satisfy the given condition but give different answers.
     
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