Practice For Tech Mahindra

Below are three conventional questions from areas and volumes. Conventional questions from areas and volumes can help you with your practice for placement papers of companies like Tech Mahindra. Though the below questions have been tagged under Tech Mahindra, similar questions can be expected in other placement papers too.

Question 1

The perimeter of a square and a rectangle is the same. If the rectangle is 12 cms. by 10 cms., then by what percentage is the area of the square more than that of the rectangle?

a) 1 b) 3 c) 5/6 d) 1/2

Answer : c) 5/6

Reason :

Given that Perimeters of square and rectangle are the same.

Perimeter of rectangle of size 12 cms and 10 cms is 2(Length + Breadth) = 2(12+10) = 44

Perimeter of square = 44. (4 x side of square)

Length of each side of the square = 44/4 =11

Area of the square = Side2 = 11 x 11 = 121 sq. meter

Area of the rectangle = Length X Breadth = 12 x 10 = 120 sq. meter

Percentage Increase of area of the square to that of the rectangle = (Area of Square - Area of Rectangle) / Area of Rectangle X 100 % = (121 - 120)/120 X 100 % = 5/6 %

Question 2

Capacity of a cylindrical vessel is 25,872 litres. If the height of the cylinder is 200% more than the radius of its base, what is the area of the base in square cms?

a) 336 b) 1232 c) 616 d) cannot be determined

Answer : c)616

Reason :

Let the radius be R and height be H

Height is 200% more than its radius.

This means H = R + 200% R = R (1 + 200/100) = 3 R

Volume of the cylinder (formula) = π R2H

It has been mentioned that volume of the cylinder is 25,872 cm3

22/7 R2H = 25,872 cm3

Substituting H = 3R we get

R = 14 cm

Area of the base = πR2 = 22/7 x 142 = 616 cm2

Question 3

If the radius of a circle is increased by 12%, then the area of the circle

a) decreases by 25.44%

b) increases by 25.44%

c) no change in area

d) decreases by 12%

Answer : b) increases by 25.44%

Reason :

Area of circle πr2 where r is the radius

Assume initially the radius was 10. Then area becomes 22/7x10x10 = 314.28 --> eq 1

Now if the radius is increased by 12%, it will become 10+(12/100)10 = 10+1.2=11.2

New area = 22/7 x 11.2x 11.2 = 394.24 --> eq 2

Increase in area in our case = eq 2 - eq 1 = 79.96

Percentage increase in area when radius is increased by 12% = Increase in Area / Original Area X 100% = 79.96 / 314.28 X 100 =25.44%