What is 225 litres of water for $75 as a rate
Answers
Answer:
A mixture of 20 kg of spirits and water contains 10% water. How much water must be added to this mixture to raise the percentage of water to 25%?
This is a simple case of Alligation
Traditional method :
20 litres => spirit = 18 water = 2
Let us add x litres water
New volume = 20 + x
New volume of water in new mixture
= 2 + x
We know, 2 + x = 25% of (20 + x)
=> 2 + x = 1/4(20 + x)
=> 8 + 4x = 20 + x
=> 3x = 12
=> x = 4 litres
Elegant method of Alligations :
When we mix 10% water with 100% water to get 25% water, we have :-
Mixture - - - - - - - pure water
10% - - - - - - - - - - - - 100%
- - - - - - - - 25% - - - - - -
75% - - - - - - - - - - - - - 15%
The ratio of existing mixture and pure water in the new liquid should be 75:15 = 5:1
So 20 litres ==> 5 parts
=> 20/5 = 4 litres ==> 1 part
Refer to this post for more details on Mixture and Alligations :