Aptitude - Alligation or Mixture - Discussion
Discussion Forum : Alligation or Mixture - General Questions (Q.No. 3)
3.
A can contains a mixture of two liquids A and B is the ratio 7 : 5. When 9 litres of mixture are drawn off and the can is filled with B, the ratio of A and B becomes 7 : 9. How many litres of liquid A was contained by the can initially?
Answer: Option
Explanation:
Suppose the can initially contains 7x and 5x of mixtures A and B respectively.
| Quantity of A in mixture left = |  |
7x - | 7 | x 9 |  |
litres = | |
7x - | 21 | litres. |
| 12 | 4 |
| Quantity of B in mixture left = | |
5x - | 5 | x 9 | |
litres = | |
5x - | 15 | litres. |
| 12 | 4 |
 |
|
= | 7 | |||||
|
9 |
 |
28x - 21 | = | 7 |
| 20x + 21 | 9 |
252x - 189 = 140x + 147
112x = 336
x = 3.
So, the can contained 21 litres of A.
Discussion:
100 comments Page 6 of 10.
Sree said:
1 decade ago
Hi Debjyoti,
Can you give the explination how you got x=36 using below equation?
7(x-9)/12:(5(x-9)+9) = 7:9
Can you give the explination how you got x=36 using below equation?
7(x-9)/12:(5(x-9)+9) = 7:9
Ankush Singh said:
6 years ago
7:5.
7:9.
Increase is part b 4.
4=9.
1=9/4.
2nd of total mix=16.
16= 9/4*16=36.
1st mix A is. 7/12*36 =21.
7:9.
Increase is part b 4.
4=9.
1=9/4.
2nd of total mix=16.
16= 9/4*16=36.
1st mix A is. 7/12*36 =21.
(36)
Vini said:
9 years ago
If 1/4th of the total is 9.
That is, 1/4 * x = 9,
Then, total (x) = 36,
Therefore, 7/12 * 36 = 21.
That is, 1/4 * x = 9,
Then, total (x) = 36,
Therefore, 7/12 * 36 = 21.
Jumcy said:
1 decade ago
See the ratio of A = 7, check the options which are divisible by 7, 21 is there, simple tricky way.
Karthikeyini said:
1 decade ago
(7x-(21/4))/((5x-(15/4))+9)
In this term how 9 occured at the end ? Can anyone explain this ?
In this term how 9 occured at the end ? Can anyone explain this ?
Karthik RS said:
1 decade ago
The Value of A is 7*x ... the only answer which is divisible by 7 is 21 .. so there you go :)
Simhachalam said:
9 years ago
@Anil Kumar Jat.
Your method is the easiest way to solve the problem. Thank you very much.
Your method is the easiest way to solve the problem. Thank you very much.
Ankita said:
1 decade ago
In the very first explanation how does 20x+21 come into picture? I mean just the 21.
Karthika said:
1 decade ago
We need to subtract 9 liters from mixture only. But why subtract from 2 liquids?
ANIL KUMAR JAT said:
1 decade ago
A B
7 : 5
7 : 9
9-5=4unit=9
1unit=9/4
16unit=36
A=36*7/12=21.
B=36*5/12=15.
7 : 5
7 : 9
9-5=4unit=9
1unit=9/4
16unit=36
A=36*7/12=21.
B=36*5/12=15.
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