# A 20 m deep well with diameter 7 m is dug and the earth from digging is evenly spread out to form a platform 22 m by 14 m. Find the height of the platform.

The volume of earth removed by digging for cylindrical well is the same volume used to make platform which is cuboidal in shape

Therefore, volume of well dug = volume of platform formed

Parameters of well

Diameter = d = 7 m

radius = r = = m

The well is 20 m deep so we can say that its height is 20 m

Height = h = 20 m

Volume of cylinder = πr2h

volume of well dug = × × 20

= × × 20

= 22 × 7 × 5

= 770 m3

Parameters for platform

Length = l = 22 m

Breadth = b = 14 m

Let height be h

Volume of cuboid = l × b × h

Volume of platform = 22 × 14 × h

= 308h m3

As volume of well dug = volume of platform formed

770 = 308h

h =

Divide numerator and denominator by 7 we get

h =

Divide numerator and denominator by 22 we get

h = = 2.5

Therefore, height of platform is 2.5 m

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Surface Area and Volume49 mins
Surface Area and Volumes43 mins
Quiz | Surface Area and Volumes42 mins
Quiz | Area Related with Circles47 mins
Champ Quiz | Area Related with the Circle45 mins
Short Cut Trick to Find Area of Triangle43 mins
Idioms and Phrases43 mins
Goprep Genius Quiz | Analogy and Classification48 mins
Acid - Types and Nomenclature52 mins
Agriculture and its Importance35 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses