So we can make an equation for this, being 7=1/3x, as that effectively says she can make 3 drawings per page.
Knowing this, we can multiply it by 3 to get x=21 (since if she can draw 3 drawings per page, we can imagine that if each drawing took a page she would need 3 times the pieces of paper), therefore she can make 21 drawings.
The angle between two vectors is:
CosФ = u - v / Magnitude(u) x magnitude(v)
Magnitude of u = SQRT(7^2 + -2^2) = SQRT(49 +4) = SQRT(53)
Magnitude of v = SQRT(-1^2 +2^2) = SQRT(1 +4) = SQRT(5)
u x v = (7 x -1) + (-2 x 2) = -7 + -4 = -11
cosФ = -11 / sqrt(53) x sqrt(5)
cosФ = -11sqrt265) / 265
Ф =cos^-1(-11sqrt265) / 265)
Ф=132.51 degrees.
1 and half hour
= 60 minutes+ 30 minutes
= 90 minutes
Now,
Uzanne need 15 minutes to do 10 problems
Uzanne need 1 minute to complete 10/15 problems
Uzanne need 90 minutes to do
= (10/15)*90
=(2/3)*90
=2*30
=60 problems
If this is algebra, then you will be using a parabola to solve this problem:
t=-b/2a
t=-8/2(-16) = 8/-32 = -1/4
t=-1/4=-0.25
h=-16(0.0625)+8(-0.25)+80
h=1-2+80
h=79
(-0.25,79)
then plug this ordered pair above and draw a line directly down the middle of it to use as a "mirror" and plug 2 different numbers(preferably 0 and 1) into the variable t to find the other two points and then reflect the two points over the "mirror" to get the last two points to graph your paprabola
