Answer:
7536 
Step-by-step explanation:
Given that:
Rate of decreasing of radius = 12 km/sec
Height of cylinder is fixed at = 2.5 km
Radius of cylinder = 40 km
To find:
The rate of change of Volume of the cylinder?
Solution:
First of all, let us have a look at the formula for volume of a cylinder.

Where
is the radius and
is the height of cylinder.
As per question statement:
= 40 km (variable)
= 2.5 (constant)

As
are constant:

Answer:
40
Step-by-step explanation:
6% of number = 6/100 × x = 6x/100 = 3x/50
Sum of the number and 6% of itself = 42.4
x + (3x/50) = 42.4
(50x+3x)/50 = 42.4
53x = 42.4 × 50
53x = 2120
x = 2120/53
x = 40
X: -2| -1| 0| 1| 2|
y: 1.25| 2.5| 5| 10| 20|