Friday, 8 April 2016

[Q] Mixture and Alligation Tricks - 2

Let us solve some CGL questions that may not seem to belong to Mixture-Alligation category, but are easier to solve via Alligation formula...


Q. 1)

Let the gain% of the remaining land be x%. Then
Given, 2/5 land is sold on loss and hence 3/5 land is sold on profit
So, Profit : Loss = 3:2
Hence 16 : (x - 10) = 3 : 2
16/(x - 10) = 3/2
or x = 62/3%
Answer : (B)
Q. 2)
His average speed for the entire journey = 61/9 km/hour
Time taken on foot : Time taken on bicycle = (9 - 61/9)/(61/9 - 4) = 4:5
Time taken on foot = 4/9 * 9 = 4 hours
Hence distance travelled on foot = (Speed on foot * Time taken on foot) = 4*4 = 16 km
Answer : (C)
Alternate method
This method is equally easy.
Let the distance travelled on foot be X km. Then distance travelled on bicycle = (61 - X)
Now he travelled for 9 hours. Hence
X/4 + (61 - X)/9 = 9
Solve for X
You will get X = 16 km

Q. 3)

Number of legs per head = 420/180 = 7/3
Now cows have 4 legs while hens have 2 legs

Cows : Hens = 1/3 : 5/3 = 1 : 5
Now total number of cows and hens = total number of heads = 180
Number of cows = 1/6 * 180 = 30
Answer : (B)


Q. 4)

A : B = 3 : 4 and B: C = 4 : 5
A : B : C = 3 : 4 : 5
Average score of classes A, B and C =

Answer : (B)

Q. 5)

The man spends 75% of his income, that means he saves 25%
Hence Expenditure : Saving = 75 : 25 = 3 : 1
Let the % increase in the savings be x.

I have written 3 : 1 as 30 : 10 so that (% increase in income - % increase in expenditure) could agree with 3 : 1 ratio. As we know 20 - 10 = 10, not 1.
So now from the figure we can see that  x - 20 = 30
Hence x = 50%
Answer : (C)


Q. 6)

If whole money is invested at 6%, then interest = 6% of 1500 = Rs. 90
If whole money is invested at 5%, then interest = 5% of 1500 = Rs. 75

Hence, Money invested at 6% :  Money invested at 5% = 10 : 5 = 2 : 1
Money invested at 5% = 1/3 * 1500 = Rs. 500
Answer : Rs. 500


If you have any doubt in this article, please drop a comment...

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25 comments:

  1. jagdish sahani8 April 2016 at 07:24

    some doubt in q. 5 how to take expenditure, saving and income at allegation formula.

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  2. jagdish sahani8 April 2016 at 07:29

    thanks for a profitable blog.....

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  3. i have a dought on ques no 2, 2nd line....

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    Replies
    1. jagdish sahani8 April 2016 at 14:00

      please draw a figure then your problem would be solved..

      Delete
  4. I couldn't get that second numerical regarding farmer. Please explain.

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  5. Very useful... thnks bde bhai...

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  6. This comment has been removed by the author.

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  7. Thanx sir.. Plzz explain remainder theorm or remainder theory concept.. That is how to find remainder???

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  8. Sir, Based on these can u provide some question sets for Practice...
    thank you Sir...!!

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  9. Hello sir, can you please explain any shortcut tricks for coding -decoding and odd-one out questions of reasoning. I have rajesh verma's maths book do we have to learn all the shortcut formulas given in each chapter of that book is it really worth and if yes , then how to remember so many shortcut formulas please help me sir.....

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  10. Sir kindly elaborate the logic behind getting p:L=3:2 in q.1....n how can i use this logic frequently??
    Thanx...

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    Replies
    1. Let us say you have 1 acre of land. You divide it in 2 parts. You sell one part at a profit of 10% and another part at a loss of 5%, such that your overall profit is 2%. In such cases you can apply allegation formula to know what part (how much acre) of the land was sold at profit and what part was sold at loss.
      In this question that part is given, 3 : 2 and we have to find the loss% instead.

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  11. In q.2....we are applying allegation on speed and at the end getting ratio of time taken...How??

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    Replies
    1. When you apply allegation on two speeds, you wont get the ratio of speeds(and you already know the ratio of the speeds).When you mix two types of teas, Rs 100/kg and Rs. 200/kg to get a third variety of Rs. 160/kg, allegation formula gives you ratio of the "quantity" (in kg) in which the two varieties should be mixed. So speed (km/hour), will give you the ratio of time (hour)

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  12. Sir Plss explain q.4...after getting 3:4:5

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    Replies
    1. A : B : C = 3 : 4 : 5
      Let the number of students in classes A, B and C be 3x, 4x and 5x , respectively
      Average score of classes A, B and C = (total score of A, B and C) / (Number of students in A, B and C)
      total score of A, B and C = 3x*83 + 4x*76 + 5x*85 ... (1)
      Number of students in A, B and C = 3x + 4x + 5x = 12x ... (2)
      Divide (1) by (2)

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  13. Sir in q.6....can we apply allegation on interest rates??
    6%-5%-17/3(avg)...got the ratio 2:1 nd thereby 500.

    ReplyDelete
    Replies
    1. Yes you can apply allegation on interest rates as well...

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    2. x 1500-x
      5% 6%

      85/15

      5/15 10/15


      thus equation will be :

      2(1500-x)=x
      x=1000

      i am confused.Plz clear

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    3. Rs. 85 interest in 1 year from a investment of Rs. 1500
      SI = P*r*t/100
      r = 17/3% [Put SI=85, P=1500, t=1]
      The mean ratio is 17/3
      Apply allegation formula-
      Money invested at 6% : Money invested at 5% = (17/3)-5 : 6- 17/3 = 2 : 1

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  14. in what proportion may these kinds of tea of prices rs 80,rs 70 and rs 50 per kg be mixed to produced a mixture of rs 60 per kg? any shortcut?

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  15. Sir, i tried using alligation concept in the below mentioned question:

    Two toys are sold at Rs. 504 each. One toy brings dealer gain of 12% and other loss of 4%. The gain or loss percent in the whole transaction is. Correct answer is 44/13 % ..I'm getting different using alligation . Pls. reply

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    Replies
    1. This comment has been removed by the author.

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  16. You clearly instructed that we can't take absolute terms in this topic and you have taken absolute term in the last topic....you can do that question by calculating the final interest

    ReplyDelete