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Question
A 21 m deep well with diameter 6 m is dug and the earth from digging is evenly spread to form a platform 27 m ✕ 11 m. Find the height of the platform.[Use `pi=22/7`]
Solution
Depth of the well, H = 21 m
Radius of the well, R = `6/2` m = 3 m
Length of the platform, l = 27 m
Breadth of the platform, b = 11 m
Let the height of platform be h.
We know
Volume of earth dug from the well = Volume of earth used to form the platform
∴ πR2H=l×b×h
⇒`22/7`×32×21=27×11×h
⇒ h = 2 m
Hence, the height of the platform is 2 m.
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