You have 10 people in company X, 10 people in company Y and 10 people in company Z. Next year, you have 7 people in company X, 3 people in company Y and 20 people in company Z.

Question

Knowing that 5 people left Z and 15 people joined Z. How many people left X ? Is it solvable ? If no why ?

Answer 1

In linear algebra, you will often perform matrix (table) operations.

Here, there are two equations with four variables. There must be four independent equations to solve for four variables.