**Problem 1:** A jar contains a mixture of two liquids A and B in the ratio 3:1. When 15 liters of the mixture is taken out and 9 liters of liquid B is poured into the jar, the ratio becomes 3: 4. How many liters of liquid A was contained in the jar?

Solution:

A : B

3 : 1

3 : 4

1-4=3

3——->9

1——–>?

4——->?4*3=12

12+15=27

**Problem 2:** A vessel is filled with liquid, which is 3 parts water and 5 parts milk. How much of the liquid should be drawn off and replaced by water to make it half water and half milk?

Solution:

w : m

3 : 5————-> 3 : 5

1 : 1*5———–>5 : 5

Allegations and mixture

is answer

**Problem 3:** In three classes X, Y, and Z an algebra test is conducted. The average score of class X is 83. The average score of class Y is 76 and the average score of class Z is 85. The average score of class X & Y is 79 and the average score of class Y & Z is 81. What is the average score of the classes X, Y, and Z?

Solution: