It will take her 2,000 minutes
Answer:

Step-by-step explanation:
The equation of the line you will find should be in the form y =mx+c , where m is the gradient and c is the y intercept.
The gradient of a line that is perpendicular to a line [of a known gradient] is the negative reciprocal of the gradient of the first. i.e. if a is the known gradient and the perpendicular gradient is b, ab = -1. Therefore the -3b=-1 and b= 1/3
you can now write y = mx +c as y = 1/3x +c
As you have been given a coordinate, you can input these values into y= 1/3x + c
-12 = 1/3(6) +c
-12 - 2 = c
c = -14
hence the equation of the line is y= 1/3x -14
Total possibilities would be:
(1,1)(1,2)(1,3)(1,4)(1,5)(1,6)
(2,1)(2,2)(2,3)(2,4)(2,5)(2,6)
(3,1)(3,2)(3,3)(3,4)(3,5)(3,6)
(4,1)(4,2)(4,3)(4,4)(4,5)(4,6)
(5,1)(5,2)(5,3)(5,4)(5,5)(5,6)
(6,1)(6,2)(6,3)(6,4)(6,5)(6,6)
You want 5 on at-least one, so mark 5th column & 5th raw.
There are 6 in both lines with 1 common = (5,5)
In short, Your Answer would be 11
Hope this helps!