We do like the following: Set the first number is a and the second is b. We have two equations: a+2xb=24, 2xa+b=21 And we have 2xa+4xb=48 or 2xa=48-4xb So: 48-4xb+b=21 or -3xb=21-48=-27 and we got b=-27:(-3)=9 and a= 6 a=6 and b=9
Each cylindrical shell has radius (the horizontal distance from the axis of revolution to the curve ); has height (the vertical distance between a point on the -axis in and the curve ).