A small terrace at a football ground comprises of 15 steps each of which is 50 m long andbuilt of solid concrete.
Each step has a rise of
m and a tread of
m. (see Fig. 5.8). Calculate the total volumeof concrete required to build the terrace.
[Hint : Volume of concrete required to build the first step 
]
Dimensions of 1st step = 50 m x 0.25 m x 0.5 m
Volume of 1st step = 6.25 m3
Dimensions of 2nd step = 50 m x 0.5 m x 0.5 m
Volume of 2ndstep = 12.5 m3
Dimensions of 3rdstep = 50 m x 0.75 m x 0.5 m
Volume of 3rdstep = 18.75 m3
Now, we have a = 6.25, d = 6.25 and n = 15
Sum of 15 terms can be calculated as follows:
S15 
= 750
Hence, the volume of concrete will be 750m3
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