There are 91 in total. Since there are 21 red cars, it would give you 21/91. Around a 23.07% chance.
Answer:
a) A student travelling to school on public transport: 15/52 or 0.231
b) A student walking to school: 16/52 or 0.308
c) A student not cycling to school: 43/52 or 0.827
Step-by-step explanation:
Total people = 52
Travel Method Frequency
Public Transport 12
Car 15
Cycle 9
Walk 16
Find the relative frequency of.
The formula used will be: 
a) A student travelling to school on public transport:
Given Frequency: 12
Size of sample space: 52
Apply formula: 
Fraction = 12/52
Decimal = 0.231
b) A student walking to school
Given Frequency: 16
Size of sample space. 52
Apply formula: 
Fraction = 16/52
Decimal = 0.308
c) A student not cycling to school.
We will consider all students except those who cycle.
12+15+16 = 43
Given Frequency: 43
Size of sample space. 52
Apply formula: 
Fraction = 43/52
Decimal = 0.827
Answer:
Answer D (the fourth one)
Step-by-step explanation:
First, we need to set up a (y−k)^2=4p(x−h). After plugging in all of your values, you would get (x-5)^2=-4(y-1). Now, we need to solve in terms of y by dividing each side by the factors that don't contain the variable. Your final solution should be 
X + 0.5y = 3
x^2 - y = 15
from the first equation:-
0.5y = 3 - x
y = 6 - 2x
Substitute for y in second equation:-
x^2 - (6 - 2x) = 15
x^2 + 2x - 21 = 0
x = [-2 +/- sqrt((4 - 4*-21)] / 2
= 3.6904 , -5.6904
Plugging in these into first equation we get
3.6904 + 0.5y = 3 so y = 2(3-3.6904) = -1.3808
-5.6904 + 0.5y = 3 so y = 2(3 + 5.6904) = 17.3808
Solution is x = 3.690, y = -1.381 ; x = -5.690, y = 17.38 ( to 4 s.f's)