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### Question 1

8 liters of Petrol costing Rs. 2/liter is mixed with 20 liters of Kerosene costing Rs. 9/liter. What is the price of the mixture per liter?

**A**

Rs. 7 per liter.

**B**

Rs. 8 per liter.

**C**

Rs. 6 per liter.

**D**

Rs. 10 per liter.

**Soln.**

**Ans: a**

We shall use the alligation formula. If a sample n_{1} has an average price of A_{1}, and another sample n_{2} has an average price of A_{2}, then the price of the mixture, A, is determined by the alligation formula as: n_{1}(A - A_{1}) = n_{2}(A_{2} - A). Putting A_{2} = 9, A_{1} = 2, n1 = 8, n2 = 20, we have 8 × (A - 2) = 20 × (9 - A), from where we get A = Rs. 7 per liter.

### Question 2

The average weight of the students of a class is 4 Kg, and the average weight of the students of another class is 14 Kg. What is the ratio of the number of students in the two classes if the combined average weight is 10 Kg?

**A**

${2/3}$.

**B**

$2{1/2}$.

**C**

$2{2/3}$.

**D**

$2{1/5}$.

**Soln.**

**Ans: a**

If a sample n_{1} has a weighted average of A_{1}, and another sample n_{2} has a weighted average of A_{2}, then the weighted average, A,of the combined samples is determined by the alligation formula as: n_{1}(A - A_{1}) = n_{2}(A_{2} - A). So the ratio is ${A_2 - A}/{A - A_1 }$. Putting A_{2} = 14, A_{1} = 4, and A = 10, we have ${14 - 10}/{10 - 4 }$, from where we get the ratio as ${2/3}$.

### Question 3

In what ratio should a vendor mix two types of pulses costing Rs. 5/Kg and Rs. 18/Kg respectively so as to get a mixture of Rs. 11/Kg?

**A**

$1{1/6}$.

**B**

$2{3/5}$.

**C**

$2{3/8}$.

**D**

$3{1/8}$.

**Soln.**

**Ans: a**

We shall use the alligation formula. If a sample n_{1} has an average price of A_{1}, and another sample n_{2} has an average price of A_{2}, then the price of the mixture, A, is determined by the alligation formula as: n_{1}(A - A_{1}) = n_{2}(A_{2} - A). Putting A_{2} = 18, A_{1} = 5, A = 11 we have n_{1} × (11 - 5) = n_{2} × (18 - 11), from where we get the required ratio as $n_1/n_2 = 7 : 6$.

### Question 4

Two types of petrols having the prices per liter as Rs. 2 and Rs. 21 are mixed in the ratio 22 : 16. What is the price of the mixture per liter?

**A**

Rs. 10 per liter.

**B**

Rs. 11 per liter.

**C**

Rs. 9 per liter.

**D**

Rs. 13 per liter.

**Soln.**

**Ans: a**

If a sample n_{1} has an average price of A_{1}, and another sample n_{2} has an average price of A_{2}, then the price of the mixture, A, is determined by the alligation formula as: n_{1}(A - A_{1}) = n_{2}(A_{2} - A). Putting A_{2} = 21, A_{1} = 2, n1 = 22, n2 = 16, we have 22 × (A - 2) = 16 × (21 - A), from where we get A = Rs. 10 per liter.

### Question 5

7 liters of Petrol costing Rs. 17/liter is mixed with 21 liters of Kerosene costing Rs. 9/liter. What is the price of the mixture per liter?

**A**

Rs. 11 per liter.

**B**

Rs. 12 per liter.

**C**

Rs. 10 per liter.

**D**

Rs. 14 per liter.

**Soln.**

**Ans: a**

We shall use the alligation formula. If a sample n_{1} has an average price of A_{1}, and another sample n_{2} has an average price of A_{2}, then the price of the mixture, A, is determined by the alligation formula as: n_{1}(A - A_{1}) = n_{2}(A_{2} - A). Putting A_{2} = 9, A_{1} = 17, n1 = 7, n2 = 21, we have 7 × (A - 17) = 21 × (9 - A), from where we get A = Rs. 11 per liter.

### More Chapters | See All...

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This Blog Post/Article "Alligations and Mixtures Quiz Set 004" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Updated on 2019-08-18.