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Word Problem Solving Example

Question:

The number of the people in class A is one and one third of the number of people in class B. If class A assigns 3 people into class B, the number of people in the two classes will be equal. How many people originally in two class?

Solution:

Let A be the number of people in class A and B is the number of people in class B. Then A = (1 + 1/3) B. From the second statement, we get A - 3 = B + 3.

Let the number of people in class B be x, then the number of people in class A is (1 + 1/3) x. If class A assigns 3 people into class B, then the two class will have equal number of people.

(1 + 1/3) x - 3 = x + 3
(4/3) x - 3 = x + 3
(4/3) x - x = 3 + 3
(4/3) x - (3/3) x = 6
(1/3) x = 6
x = 18
the number of people in class B is 18
(1 + 1/3) x = (4/3) (18) = 4 × 6 = 24
the number of people in class A is 24

Therefore, the number of people in class A is 24 and the number of people in class B is 18. When the class A assigns 3 people into class B, bothe class will have the equal people that is 21.