Second question:
sum of all the interior angle 180*(8-2)=1080 degree
sum of one interior angle 1080/8=135 degree
The vector equation of the line through the origin perpendicular to the plane is
.. (x, y, z) = t(2, 3, -1)
so the point of interest will satisfy
.. 2(2t) +3(3t) -(-t) = -3
.. 14t = -3
.. t = -3/14
and its coordinates are (x, y, z) = (-3/7, -9/14, 3/14)
3/4 = 9/12
2/3 = 8/12
9/12 - 8/12 = 1/12
So Johnny ran for 1/12 of an hour longer than Angie.
1st digit can be 1-9 which is 9 numbers
2nd digit can be 1-9 which is 9 numbers
3rd digit can be 4-7 which is 4 numbers.
Total combinations = 9 x 9 x 4 = 324
