The radi us of cross-se ct ion of a sol id
cyl indric al rod of iron is 50 cm. The
cylinder is melted down and formed in to six
solid spherical balls of the same radius as that
of the cylinder. The length of the rod (in
meters) will be –

The sum of two numbers is 520. If the
bigger number is decreased by 4% and the
smaller number is increased by 12%, then
the numbers obtained are equal. The smaller
number is –

Arbind spends 75% of his income and saves
the rest. His income is increased by 20% and
he increased his expenditure by 10%. Then
the increase in savings in percentage is –

Two alloys are made up of both copper and tin.
The ratio of copper and tin in the first alloy is
1 : 3 and in the second alloy is 2 : 5. In what
ratio should the two alloys be mixed, to
obtain a new alloy in which the ratio of tin
and copper be 8 : 3 ?

The elevation of the top of a tower from a point
on the ground is 45°. On travelling 60 m from
the point towards the tower the elevation of
the top becomes 60°. The height of the tower
is –

50 men took a dip in a water tank 40 m long
and 20 m broad on a religious day. If the
average displacement of water by a man is
4 m
3
, then the rise in the water level in the
tank will be –