Sanjay S. answered • 01/19/15

Expert, Patient and Motivated Tutor for Math, Science and Test Prep

Bailey,

Assume Mr. Adrian has been teaching for A years, Ms. Betty for B years and Mr. Charlie for C years

A + B = 36

B + C = 22

A + C = 28

You have 3 equations in 3 unknowns which can be solved in multiple ways.

Adding all 3 equations

2A + 2B + 2C = 86

A + B + C = 43

This is your new eq.

Subtract first eq. from the new eq, C = 7

Subtract second eq from the new eq , A = 21

Subtract third eq. from the new eq: B = 15

This gives you the number of years each has taught.