After Sean had stacked up 11 chairs in the school field after a function, he noticed 3 things. Firstly, each of the chairs was stacked the same height above the other. Secondly, the foot of the sixth chair was 58.5 cm above that of the first. Thirdly, the chairs reached a height of 216.5 cm. What is the height of each chair?
Number of chairs that contributed to the height of 58.5 cm above the first chair
= 6 - 1
= 5

Height increase with each additional stacked chair
= 58.5 ÷ 5
= 11.7 cm

Number of chairs stacked on top of the first chair
= 11 - 1
= 10

Height increase of 10 additional stacked chairs
= 10 x 11.7
= 117 cm

Height of one chair
= 216.5 - 117
= 99.5 cm

Answer(s): 99.5 cm