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 4 of 10.
Dhivya said:
8 years ago
Initial A:B 7:5 ->12Parts.
New ratio A:B 7:9.
In the new ratio only 4 parts is changed so, 4parts=9litre.
for 12 parts =27litre + 9Litre.
Initial Litre is 36.
for Initial liquid A :7/12 *36 = 21Litre.
New ratio A:B 7:9.
In the new ratio only 4 parts is changed so, 4parts=9litre.
for 12 parts =27litre + 9Litre.
Initial Litre is 36.
for Initial liquid A :7/12 *36 = 21Litre.
Dhivya said:
8 years ago
Initial A:B 7:5 ->12Parts.
New ratio A:B 7:9.
In the new ratio only 4 parts is changed so, 4parts=9litre.
for 12 parts =27litre + 9Litre.
Initial Litre is 36.
for Initial liquid A :7/12 *36 = 21Litre.
New ratio A:B 7:9.
In the new ratio only 4 parts is changed so, 4parts=9litre.
for 12 parts =27litre + 9Litre.
Initial Litre is 36.
for Initial liquid A :7/12 *36 = 21Litre.
SAM said:
8 years ago
A : B.
7 : 5
7 : 9
Here A is not changed ,but B added 9 liters more,
B = 9 - 5 = 4 difference by adding 9 on [ 9+7=16].
9/4 * 16 = 36.
Total is 36.
A =36 * 7/12 = 21.
7 : 5
7 : 9
Here A is not changed ,but B added 9 liters more,
B = 9 - 5 = 4 difference by adding 9 on [ 9+7=16].
9/4 * 16 = 36.
Total is 36.
A =36 * 7/12 = 21.
Kashif said:
8 years ago
Totally wrong answers. Why because total qty of B solution after drawn off and portion of B added is this,
5/12*x - 9*5/12 + 4y < where why is total qty of B added after drawn off and 4=9-5>.
5/12*x - 9*5/12 + 4y < where why is total qty of B added after drawn off and 4=9-5>.
Trilok said:
1 decade ago
We need to find how many liters of liquid A present in the can initially. So it is given that ratio is 7:5. So clearly it is a multiple of 7. And, by looking at the options we get the answer as 21.
Veeresh nj said:
6 years ago
7:5 = 7 * 5 = 35.
7:9 = 7 * 9 = 63.
Now subtract both values;
63 - 35 = 28.
Now u see common value in 7:5 and 7:9.
Here 7 is common to subtract this value with 28.
A = 28 - 7 = 21.
A = 21.
7:9 = 7 * 9 = 63.
Now subtract both values;
63 - 35 = 28.
Now u see common value in 7:5 and 7:9.
Here 7 is common to subtract this value with 28.
A = 28 - 7 = 21.
A = 21.
(27)
Sai sekhar said:
8 years ago
Given ratios A:B is 7:9 and asked the initial quantity for that we check the options which are the multiples of 7.
In this case, 21 is only multiple 7. So directly we can say 21 is the answer.
In this case, 21 is only multiple 7. So directly we can say 21 is the answer.
Jamshaid said:
3 years ago
The Correct solution is;
Change in old ratio to new ratio;
7X / (5X+9) = 7/9,
X = 9/4.
Old A = 7X + 9litre * 7/12 (A's part in 9l drew).
= 7*(9/4)+9*7/12 = 28.7/20L A's share in old mixture.
Change in old ratio to new ratio;
7X / (5X+9) = 7/9,
X = 9/4.
Old A = 7X + 9litre * 7/12 (A's part in 9l drew).
= 7*(9/4)+9*7/12 = 28.7/20L A's share in old mixture.
(16)
ESWARARAO S said:
8 years ago
When mixture removed, same 7:9 remains.
7 : 5 when Mixture B,
Gained 3 points of B mixture for 9 litres.
So 1 Point of mixture is 3 litres,
And, 7 Points of A mixture is 7 * 3= 21 litres.
7 : 5 when Mixture B,
Gained 3 points of B mixture for 9 litres.
So 1 Point of mixture is 3 litres,
And, 7 Points of A mixture is 7 * 3= 21 litres.
Anonymous said:
4 years ago
@All.
Here, after performing n operations on a total of x litres replacing y liters, the final amount present is x(1+y/x)^n.
Substituting values, 12(1+9/12) = 12+9 = 21.
Here, after performing n operations on a total of x litres replacing y liters, the final amount present is x(1+y/x)^n.
Substituting values, 12(1+9/12) = 12+9 = 21.
(29)
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