mixtures and alligation practice problems with solutions

mixtures and alligation practice problems with solutions
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Question 1: In what proportion must tea at Rs. 7.50 per kg be mixed with tea at Rs. 10.50 per kg to produce a mixture worth Rs. 8.50 per kg?
[A] 1 : 2
[B] 2 : 1
[C] 1 : 1
[D] 2 : 3
Show Answer
Option # 2

Explanation

Solution :

Using the formula of alligation,

 required ratio =2: 1


Question 2: Metal A costs Rs. 8.40 per gm and Metal B Rs. 0.21 per gm. In what proportion must these metals be mixed so that gram of the mixture may be worth Rs. 5.67?
[A] 1 : 2
[B] 1 : 3
[C] 2 : 1
[D] 2 : 3
Show Answer
Option # 3

Explanation

Solution :

Using the formula of alligation,

required ratio= 2: 1 


Question 3: A 15-litre mixture contains 20% alcohol and the rest water. If 3 litres of water is mixed in it, then the percentage of alcohol in the new mixture will be
[A] 17%
[B]
[C]
[D] 15%
Show Answer
Option # 2

Explanation

Solution :

Initially, the mixture contains 3 litres of alcohol and 12 litres of water. Afterwards, the mixture contains 3 litres of alcohol and 15 litres of water.

percentage of alcohol.


Question 4: A mixture of 20 kg of water and spirit contains 10% water. How much water must be added to this mixture to raise the percentage of water to 25%?
[A] 4 kg
[B] 5 kg
[C] 8 kg
[D] 30 kg
Show Answer
Option # 1

Explanation

Solution :

Water

In the second mixture:

75 kg spirit is contained in a mixture of 100 kg

18 kg spirit is contained in a mixture of.

So, water to be added=24-20=4 kg


Question 5: A sum of money is sufficient to pay Sachin’s salary of 45 days and kale’s salary for 60 days. For how many days can the sum pay the salary of both?
[A] 25 days
[B] 280/11 days
[C] 180/7 days
[D] 270/11 days
Show Answer
Option # 3

Explanation

Solution :

Sachin's salary for one day =  1/45th of the sum of money.

For kale's salary for one day = 1/60 of the sum of money.

=> (Sachin + kale)'s salary for one day= 1/45+1/60=7/180th of the sum.

Hence, when they both work together, the sun will last for 180/7 days.