Question

Mathematics teacher of a school took her class 9th students to show Red fort. It was a part of their

educational trip. The teacher has interest in history as well. She narrated the facts of Red Fort to

students. Then the teacher said in this monument one can find combination of solid figures. There are

2 pillars which are cylindrical in shape. Also 2 domes at the corners, which are hemispherical.

Seven smaller domes at the centre. Flag hoisting ceremony on Independence Day takes place

(i) How much cloth material will be required to cover 2 big domes each of radius 2.5metres?

(Take ? =

22)

7

a) 75m2

b) 78.57m2

c) 87.47m2

d) 25.8m2

(ii) Write the formula to find the volume of a cylindrical pillar.

a) Πr2

h b) Πrl c) Πr(l+r) d) 2Πr

(iii) Find the lateral surface area of two pillars if height of the pillar is 7m and radius of the base of

the radius of the base is 1.4m.

a) 112.3cm2

b) 123.2m2

c)90m2

d)345.2cm2

(iv) How much is the volume of a hemisphere if the radius of the base is 3.5m?

a) 85.9m3

b) 80m3

c) 98m3

d)89.3m3

(v) What is the ratio of sum of volumes of two hemispheres of radius 1cm each to the volume of

a sphere of radius 2cm?

a) 1:1 b) 1:8 c) 8:1 d) 1:16
​

Answer 1

$\huge\star{\red{Q}{uestion}}\star\:$

Sum of the digits of a two-digit number is 12. The given number exceeds the number obtained by interchanging the digits by 36. Find the given

number.

$\huge\star{\red {A}{nswer}}\star\:$

$\huge\underline {Let,}$

The tens digit of the required number be x

and the units digit be y

$\huge\underline {Then,}$

x + y = 12 ......... eq. (1)

Required number = (10x + y)

Number obtained on reversing the digits = (10y + x)

$\huge\underline {Therefore,}$

(10y + x) - (10x + y) = 18

9y - 9x = 18

x - y = 12 ......... eq. (2)<br>

On adding eq. (1) and eq. (2)

$\huge\underline {We\: get}$

x + y + y - x = 12 +2

2y = 14

y = 2

$\huge\underline {Therefore}$

x = 5

Hence, the required number is 57

$\huge\green { Hope\: this\: helps\: you}$

$\huge\red {\mathtt{@SpammingKing\: here}}$

Answer 2

please write rhe correct qyestion