Question

Plz................ Solve q no. 28................... .

Answer 1

Namaste.

Let the outer radius be=R

Let the inner radius be=r

Hieght of cylinder=14cm

Then outer curved surface area=2πRh

Inner curved surface area=2πrh

A.T.Q

Outer curved surface area - inner curved surface area=44cm^2

2πRh-2πrh=44cm^2

2πh(R-r)=44

2×22/7×14(R-r)=44

(R-r)=44×7/44×14

R-r=1/2 or 0.5. (i)

Now

Volume of cylinder=99cm^3

πh(R^2-r^2)=99

22/7×14(R+r)(R-r)=99..(R^2-r^2=(R-r)(R+r)

44×1/2(R+r)=99..............(since R-r=1/2)

22(R+r)=99

R+r=99/22

R+r=9/2 or 4.5. (ii)

subtracting eq i from ii

R+r=4.5

R-r=0.5

- + -

0+2r=4

2r=4

r=2

Putting value of r in eq i

R-r=0.5

R-2=0.5

R=2+0.5

R=2.5

ANSWER=Outer Radius=2.5 and Inner radius=2cm

Hope it helps