Question

Elias woke up in the middle of the night and, due to a power cut, it was very dark in his apartment. Elias* pencils were in one large box and he remembered that there were 11 blue pencils, 14 black pencils and 8 grey pencils in the box.

As Elias didn't see the colour of the pencils, he picked as many pencils from the box so that he would have at least two black poncils.
What was the minimum amount of pencils Ellas needed to pick to ensure he would get at least two black pencils?

Answer 1

Why did Elias wake up in the middle of the night in the first place and go to find colour pencils?

Anyways the answer would be 21 colour pencils.

Explanation:

Elias would need to pick up 21 colour pencils to ensure he would get at least 2 black pencils because if you added up the number or blue pencils and grey pencils you would get 19. Then you would add 2 for the minimum amount black colour pencils (at least to ensure you got at least 2).

Answer 2

21

Explanation:

Given 11 blue, 14 black, and 8 grey pencils, you want the minimum number of pencils that will guarantee you have 2 black pencils.

Not black

There are 11 +8 = 19 pencils that are not black. If Elias happened to draw all of those first, he would need to draw 2 more to guarantee he has 2 black pencils.

Elias needs to pick 19+2 = 21 pencils to ensure at least 2 are black.