algebra aptitude tricks - Wikitechy https://www.wikitechy.com/interview-questions/tag/algebra-aptitude-tricks/ Interview Questions Tue, 07 Sep 2021 11:05:55 +0000 en-US hourly 1 https://wordpress.org/?v=6.9 https://www.wikitechy.com/interview-questions/wp-content/uploads/2025/10/cropped-wikitechy-icon-32x32.png algebra aptitude tricks - Wikitechy https://www.wikitechy.com/interview-questions/tag/algebra-aptitude-tricks/ 32 32 What is the radius of the circular plate of thickness 1 cm made by melting a sphere of radius 3 cm ? https://www.wikitechy.com/interview-questions/geometry/what-is-the-radius-of-the-circular-plate-of-thickness-1-cm-made-by-melting-a-sphere-of-radius-3-cm/ https://www.wikitechy.com/interview-questions/geometry/what-is-the-radius-of-the-circular-plate-of-thickness-1-cm-made-by-melting-a-sphere-of-radius-3-cm/#respond Tue, 17 Aug 2021 16:11:06 +0000 https://www.wikitechy.com/interview-questions/?p=1817

What is the radius of the circular plate of thickness 1 cm made by melting a sphere of radius 3 cm ?

A. 6 cm

B. 5 cm

C. 4 cm

D. 7 cm

Answer : A. 6 cm

Explanation :

Given that radius of sphere r = 3 cm
Given that thickness of the plate h = 1 cm

Given that a sphere is melt to produce a circular plate.
Since nothing is added or subtraced then volume of sphere and circular plate both will be equal.
Volume of sphere 
Volume of circular plate 
set both volumes equal to each other



36 = r2
6 = r
Hence the radius is 6 cm.

]]> https://www.wikitechy.com/interview-questions/geometry/what-is-the-radius-of-the-circular-plate-of-thickness-1-cm-made-by-melting-a-sphere-of-radius-3-cm/feed/ 0 In City A population is 68000, decreasing at a rate of 80 per year City B having population 42000 increasing at a rate of 120 per Year. In how many years both the cities will have same population ? https://www.wikitechy.com/interview-questions/algebra/in-city-a-population-is-68000-decreasing-at-a-rate-of-80-per-year-city-b-having-population-42000-increasing-at-a-rate-of-120-per-year-in-how-many-years-both-the-cities-will-have-same-population/ https://www.wikitechy.com/interview-questions/algebra/in-city-a-population-is-68000-decreasing-at-a-rate-of-80-per-year-city-b-having-population-42000-increasing-at-a-rate-of-120-per-year-in-how-many-years-both-the-cities-will-have-same-population/#respond Thu, 05 Aug 2021 10:55:54 +0000 https://www.wikitechy.com/interview-questions/?p=1587

City A population is 68000, decreasing at a rate of 80 per year City B having population 42000 increasing at a rate of 120 per Year. In how many years both the cities will have same population ?

City A population = 68000
Amount of decrease = 68000-80X
City B population = 42000
Amount of increase = 42000+120x

If both cities will have same population then

68000-80x = 42000+120x
68000-42000 = 120x+80x
26000 = 200x
x = 26000/200
Ans = 130
In 130 years both cities will have same population

Check:

City A population = 68000-80* 130
= 68000-10400
= 57600
City B population = 42000+ 120*130
= 42000+15600
= 57600

]]> https://www.wikitechy.com/interview-questions/algebra/in-city-a-population-is-68000-decreasing-at-a-rate-of-80-per-year-city-b-having-population-42000-increasing-at-a-rate-of-120-per-year-in-how-many-years-both-the-cities-will-have-same-population/feed/ 0