7
Q:

# Find the ratio in which rice at Rs. 7.20 a kg be mixed with rice at Rs. 5.70 a kg to produce a mixture worth Rs. 6.30 a kg.

 A) 1:3 B) 2:3 C) 3:4 D) 4:5

Explanation:

By the rule of alligation:
Cost of 1 kg rice of 1st kind                  Cost of 1 kg rice of 2nd kind

Required ratio = 60 : 90 = 2 : 3

Q:

An alloy of copper and bronze weight 50g. It contains 80% Copper. How much copper should be added to the alloy so that percentage of copper is increased to 90%?

 A) 45 gm B) 50 gm C) 55 gm D) 60 gm

Explanation:

Initial quantity of copper = = 40 g

And that of Bronze = 50 - 40 = 10 g

Let 'p' gm of copper is added to the mixture

=> = 40 + p

=> 45 + 0.9p = 40 + p

=> p = 50 g

Hence, 50 gms of copper is added to the mixture, so that the copper is increased to 90%.

3 129
Q:

A man pays Rs. 6.40 per litre of milk. He adds water and sells the mixture at Rs. 8 per litre, thereby making 37.5% profit. The proportion of water to milk received by the customers is

 A) 1 : 10 B) 10 : 1 C) 9 : 11 D) 11 : 9

Explanation:

Customer ratio of Milk and Water is given by

Milk          ::        Water

6.4                         0

$\frac{64}{11}$

=> Milk : Water = 110 : 11 = 10 : 1

Therefore, the proportionate of Water to Milk for Customer is 1 : 10

4 134
Q:

In a 40 litre mixture of alcohol & water, the ratio of alcohol and water is 5 : 3. If 20% of this mixture is taken out and the same amount of water is added then what will be the ratio of alcohol and water in final mixture?

 A) 1:1 B) 2:1 C) 3:1 D) 1:2

Explanation:

Quantity of alohol in the mixture = 40 x 5/8 = 25 lit

Quantity of water = 40 - 25 = 15 lit

According to question,

Required ratio =

7 360
Q:

In a 100 litre of mixture the ratio of milk and water is 6:4. How much milk must be added to the mixture in order to make the ratio 3 : 1?

 A) 85 B) 60 C) 55 D) 45

Explanation:

Let M litres milk be added

=>

=> 60 + M = 120

=> M = 60 lit.

5 210
Q:

A mixture contains 25% milk and rest water. What percent of this mixture must taken out and replaced with milk so that in mixture milk and water may become equal.

 A) 31.8% B) 31% C) 33.33% D) 29.85%

Explanation:

Now, take percentage of milk and applying mixture rule

25          100

50

50            25  = 2 : 1

Hence required answer =  1/3 or 33.33%

9 270
Q:

The concentration of glucose in three different mixtures (glucose and alcohol) is  respectively. If 2 litres, 3 litres and 1 litre are taken from these three different vessels and mixed. What is the ratio of glucose and alcohol in the new mixture?

 A) 3:2 B) 4:3 C) 2:3 D) 3:4

Explanation:

Concentration of glucose are in the ratio = $\frac{1}{2}:\frac{3}{5}:\frac{4}{5}$

Quantity of glucose taken from A = 1 liter out of 2

Quantity of glucose taken from B = 3/5 x 3 = 1.5 lit

Quantity of glucose taken from C = 0.8 lit

So, total quantity of glucose taken from A,B and C = 3.6 lit

So, quantity of alcohol = (2 + 3 + 1) - 3.6 = 2.4 lit

Ratio of glucose to alcohol = 3.6/2.4 = 3:2

7 397
Q:

A milkman claims to sell milk at its cost price, still, he is making a profit of 30% since he has mixed some amount of water in the milk. What is the % of milk in the mixture?

 A) 71.02% B) 76.92% C) 63.22% D) 86.42%

Explanation:

Let the milk he bought is 1000 ml

Let C.P of 1000 ml is Rs. 100

Here let he is mixing K ml of water

He is getting 30% profit

=> Now, the selling price is also Rs. 100 for 1000 ml

=> 100 : K%

= 100 : 30

10 : 3 is ratio of milk to water

=> Percentage of milk = 10 x 100/13 = 1000/13 = 76.92%

9 683
Q:

The milk and water in two vessels A and B are in the ratio 4:3 and 2:3 respectively. In what ratio the liquids in both the vessels be mixed to obtain a new mixture in vessel c consisting half milk and half water?

 A) 8:3 B) 6:7 C) 7:5 D) 11:7

Explanation:

Milk in 1-litre mixture of A = 4/7 litre.

Milk in 1-litre mixture of B = 2/5 litre.

Milk in 1-litre mixture of C = 1/2 litre.

By rule of alligation we have required ratio X:Y

X                  :                 Y

4/7                                2/5

\                      /

(Mean ratio)
(1/2)

/                      \

(1/2 – 2/5)     :       (4/7 – 1/2)

1/10                      1/1 4

So Required ratio = X : Y = 1/10 : 1/14 = 7:5