52
Q:

# A can contains a mixture of two liquids A and B in 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?

 A) 10 B) 20 C) 21 D) 25

Explanation:

Suppose the can initially contains 7x and 5x litres of mixtures A and B respectively

Quantity of A in mixture left =$\inline (7x-\frac{7}{12}\times 9)=(7x-\frac{21}{4})$ litres.

Quantity of B in mixture left =  $\inline (5x-\frac{5}{12}\times 9)=(5x-\frac{15}{4})$litres.

$\inline \frac{(7x-\frac{21}{4})}{(5x-\frac{15}{4}+9)}=\frac{7}{9}$

$\inline \Rightarrow \frac{28x-21}{20x+21}=\frac{7}{9}$

$\inline \Rightarrow 252x-189=140x+147$

$\inline \Rightarrow x=3$

So, the can contained 21 litres of A.

Q:

A mixture of 70 litres of Fruit Juice and water contains 10% water. How many litres of water should be added to the mixture so that the mixture contains 12 1/2% water   ?

 A) 2 lit B) 4 lit C) 1 lit D) 3 lit

Explanation:

Quantity of fruit juice in the mixture = 90/100 (70) = 63 litres.

After adding water, juice would form 87 1/2% of the mixture.

Hence, if quantity of mixture after adding x liters of water, (87 1/2) / 100 x = 63 => x = 72

Hence 72 - 70 = 2 litres of water must be added.

2 61
Q:

A mixture of 150 liters of wine and water contains 20% water. How much more water should be added so that water becomes 25% of the new mixture ?

 A) 5 lit B) 10 lit C) 15 lit D) 20 lit

Explanation:

Number of liters of water in 150 liters of the mixture = 20% of 150 = 20/100 x 150 = 30 liters.
P liters of water added to the mixture to make water 25% of the new mixture.
Total amount of water becomes (30 + P) and total volume of mixture is (150 + P).
(30 + P) = 25/100 x (150 + P)
120 + 4P = 150 + P => P = 10 liters.

1 100
Q:

640 ml of a mixture contains milk and water in ratio 6:2. How much of the water is to be added to get a new mixture containing half milk and half water ?

 A) 360 ml B) 320 ml C) 310 ml D) 330 ml

Explanation:

Here total parts of milk and water in the solution is 6+2 = 8 parts
1part = 640/8 = 80
old mixture contains 6parts of milk and 2 parts of water(6:2).
To get new mixture containing half milk and half water, add 4parts of water to the old mixture then 6:(2+4) to make the ratio same.
i.e, 4 x 80 = 320 ml.

4 435
Q:

Equal quantities of three mixtures of milk and water are mixed in the ratio 1:2, 2:3 and 3:4. The ratio of water and milk in the mixture is ?

 A) 193 : 122 B) 97 : 102 C) 115 : 201 D) 147 : 185

Explanation:

Given the three mixtures ratio as (1:2),(2:3),(3:4)

(1+2),(2+3),(3+4)

Total content = 3,5,7

Given equal quantities of the three mixtures are mixed, then LCM of 3, 5, 7 = 105

105/3 = 35 , 105/5 = 21 , 105/7 = 15

Now, the individual equal quantity ratios are (35x1, 35x2), (21x2, 21x3), (15x3, 15x4)

(35,70), (42,63), (45,60)

So overall mixture ratio of milk and water is

35+42+45 : 70+63+60

122:193

But in the question asked the ratio of water to milk = 193 : 122

3 351
Q:

In a mixture of milk and water the proportion of water by weight was 75%. If in 60 gm of mixture 15 gm water was added, what would be the percentage of water ? (Weight in gm)

 A) 80% B) 70% C) 75% D) 62%

Explanation:

Water in 60 gm mixture=60 x 75/100 = 45 gm. and Milk = 15 gm.

After adding 15 gm. of water in mixture, total water = 45 + 15 = 60 gm and

weight of a mixture = 60 + 15 = 75 gm.

So % of water = 100 x 60/75 = 80%.