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  1. H

    Year 11 Permutations (3 U)

    This is from the Cambridge Yr 11 Ext 1 textbook
  2. H

    Quantitative chemistry

    The answers in the textbook are a bit off with the rounding...so could someone please do part b) ?
  3. H

    Calculus

    OMG thank you!!! i hope i'm not bothering you too much with all these questions haha
  4. H

    Calculus

    a) Find the x-coordinates of the points P and Q on y = (x − 7)^2 +3 such that the tangents at P and Q have gradients 1 and −1 respectively. b) Show that the square formed by the tangents and normals at P and Q has area 1/2 I got part a ... The coordinates are P= (7.5, 3.25), Q= (6.5, 3.25)...
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    Chemistry: Percentage Composition by Mass

    Thanks! Did you manage to do q7 by any chance? :)
  6. H

    Chemistry: Percentage Composition by Mass

    Question 6 A) Carbon monoxide is 43% carbon by mass; nitrous oxide is 30% nitrogen by mass. For both gases, the remainder is oxygen. In a mixture containing 5g of each gas, what is the mass of oxygen present? Question 7) In a carbon monoxide and nitrous oxide mixture, an analyst determines...
  7. H

    Year 11 Chemistry Bonding

    I was a bit confused so I thought I should ask here. In questions such as "indicate the type of bonding holding the atoms or ions in the compound together"...do you write either ionic/covalent/metallic or do you have to mention intermolecular forces as well (polar/non-polar, hydrogen bonding...
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    Year 11 Permutations (arrangements in a circle)

    3) Bob, Betty, Ben, Brad and Belinda are to be seated at a round table. In how many ways can this be done: a if there are no restrictions, b if Betty sits on Bob’s right-hand side, c if Brad is to sit between Bob and Ben, d if Belinda and Betty sit apart, e if Ben and Belinda sit apart, but...
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    Year 11 Permutations (3 U)

    That's helpful advice, thanks!
  10. H

    Year 11 Permutations (3 U)

    Yes that’s right!
  11. H

    Year 11 Permutations (3 U)

    The answer for part c is correct but part d seems to add up to a different number. I thought about it a bit more...so in the 4 digit combinations, you can't do 4! because the first number has to be 1 or 3 (question asks numbers less than 4000) so it would be (1 x 3!) x 2 -->just for working out...
  12. H

    Year 11 Permutations (3 U)

    21 Numbers less than 4000 are formed from the digits 1, 3, 5, 8 and 9, without repetition. a) How many such numbers are there? b) How many of them are odd? c) How many of them are divisible by 5? d) How many of them are divisible by 3? Can somebody please help me with part c and d
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    Year 11 Perms and Combs help (maths ext 1)

    Yep..chapter 14c i'm pretty sure
  14. H

    Year 11 Perms and Combs help (maths ext 1)

    Yes that's correct, thanks!
  15. H

    Year 11 Perms and Combs help (maths ext 1)

    14 a How many seven-letter words can be formed without repetition from the letters of the word INCLUDE? b How many of these do not begin with I? c How many end in L? d How many have the vowels and consonants alternating? e How many have the C immediately following the D? f How many have the...
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