It would be C.60 If you add the column of 16-20 and 21-25 it makes 60.
It would be nice to know some options, but here's Morris's speed.
Since Morris is traveling at three feet per second, we want to change it to per hour.
3 * 3600 = 10800 feet per hour
And we would want to convert that to miles per hour.
10800/5280 is about 2, more specifically 2.05 ish.
So Morris is traveling 2 mph less then 50, or about 48 mph.
Answer: The correct option is fourth, i.e., 1935 cm³.
Explanation:
It is given that the vase is 30 cm tall and the hexagon base has an area of 64.5 cm².
The area of a hexagon base is,

Where, a is the side length.
The volume of the a hexagon glass is,


Where, A is area of base of hexagon and h is height of the hexagon glass.


Therefore the volume of the glass is 1935 cm³ and the glass can hold 1935 cm³ water. So, fourth option is correct.
The solution depends on the value of

. To make things simple, assume

. The homogeneous part of the equation is

and has characteristic equation

which admits the characteristic solution

.
For the solution to the nonhomogeneous equation, a reasonable guess for the particular solution might be

. Then

So you have


This means


and so the general solution would be
The cross product of the normal vectors of two planes result in a vector parallel to the line of intersection of the two planes.
Corresponding normal vectors of the planes are
<5,-1,-6> and <1,1,1>
We calculate the cross product as a determinant of (i,j,k) and the normal products
i j k
5 -1 -6
1 1 1
=(-1*1-(-6)*1)i -(5*1-(-6)1)j+(5*1-(-1*1))k
=5i-11j+6k
=<5,-11,6>
Check orthogonality with normal vectors using scalar products
(should equal zero if orthogonal)
<5,-11,6>.<5,-1,-6>=25+11-36=0
<5,-11,6>.<1,1,1>=5-11+6=0
Therefore <5,-11,6> is a vector parallel to the line of intersection of the two given planes.