Question

Two solid cylinders, one with diameter 40 cm and height 20 cm and the other with radius 20cm and height 40 cm,are melted and recasted into a third cylinder of height 5cm. Find the diameter of the cylinder formed.​

Answer 1

Answer:

Correct option is A)

1st solid cylinder diameter = 60 cm, radius= 30 cm

and height =30 cm

2nd solid cylinder radius 30 cm and height 60 cm

3rd solid cylinder=height 10 cm

As per question,

Volume of 1st solid cylinder+Volume of 2nd solid cylinder= Volume of 3nd solid cylinder

V

1

+V

2

=V

3

πr

2

h+πr

2

h=πr

2

h

π(30)

2

∗30+π(30)

2

∗60=πr

2

∗10

(30)

2

∗30+(30)

2

∗60=r

2

∗10

r

2

=8100

r=90

Diameter=2r=180cm