$3$ cubes of side $3, 4$ and $5$ $cm$ respectively,are melted to form a new cube. The side of the new cube is......$cm$

The ratio of total surface area to lateral surface area of a cylinder whose radius is $80 \text{ cm}$ and height $20 \text{ cm}$ is: (in $:1$)

$A$ right circular cylinder having diameter $21\, cm$ and height $38\, cm$ is full of ice cream. The ice cream is to be filled in cones of height $12\, cm$ and diameter $7\, cm$ having a hemispherical shape on the top. The number of such cones to be filled with ice cream is

$A$ cylindrical iron rod is $70\, cm$ long. The diameter of its end portion is $2\, cm$. What is its weight,reckoning a $cm^3$ of iron to weigh $10\, grams$? (in $kg$)

$A$ cone,a hemisphere,and a cylinder stand on equal bases and have the same height. The ratio of their volumes is:

$A$ circular wire of radius $42 \, cm$ is cut and bent in the form of a rectangle whose sides are in the ratio $6:5$. Find the smaller side of the rectangle (in $cm$).