Mathematics

Problem

A straight ramp is constructed with

15

wooden beams placed one after another. The thickness of the first beam is

10\,\text{cm}

, and each successive beam is thicker than the previous one by the same amount. If the total thickness of all

15

beams together is

240\,\text{cm}

, what is the thickness of the last beam? a)

20\,\text{cm}

23\,\text{cm}

22\,\text{cm}

24\,\text{cm}