The cross product of two vectors gives a third vector

that is orthogonal to the first two.

Normalize this vector by dividing it by its norm:

To get another vector orthogonal to the first two, you can just change the sign and use

.
What we want to do first is isolate the variable. To do this we need to multiply each side by 5 to remove the fraction
5 * 5 = 5*

w
Simplify the right side
5 *

w = 1w
Now simplify the left side
5 * 5 = 25
Then we get...
25 = w
There's your answer!
It would be 21 because 7 times 3 equals 21 and the way you get that is 3 drawings per paper
144 is the lowest hoped this helped