Three teachers were discussing how long they had been teaching.

Alex and Blake had been teaching for a total of 36 years.

Charlie and Blake had been teaching for a total of 22 years.

Charlie and Alex had been teaching for a total of 28 years.

How long had each been teaching?

Puzzle Copyright © Kevin Stone

workings hint hide answer print

Share link: www.brainbashers.com

Answer

Alex had been teaching for 21 years.

Blake had been teaching for 15 years.

Charlie had been teaching for 7 years.

Reasoning

Let Alex = A, Blake = B and Charlie = C, then:

[1] A + B = 36

[2] C + B = 22

[3] C + A = 28

If we use [3] - [2] we have:

[4] A - B = 6

If we use [1] + [4] we have:

2A = 42

A = 21

By [1] B = 15. By [3] C = 7.

**Note:** BrainBashers has a Dark Mode setting.