Class 10

Math

All topics

Sequences and Series

A small terrace at a football ground comprises of 15 steps each of which is 50 m long and built of solid concrete. Each step has a rise of $41 $m and a tread of $21 $m. Calculate the total volume of concrete required to build the terrace.

Volume of 2nd step=$42 ⋅21 ⋅50=8100 $

Volume of 3rd step=$43 ⋅21 ⋅50=8150 $

Volume are in AP

$S_{n}=2n (2a+(n−1)d)$

$S_{15}=215 (2(850 )+(15−1)50)$

$S_{15}=750m_{3}$