Part 1: The general form for this matches y^2 = -4cx, which implies that this opens to the left. (Imagine assigning any value of y, whether positive or negative, which would result in a positive left-hand value. Then to match this sign, the value of x must be negative so that the right-hand side becomes positive as well.)
Part 2: The distance from the vertex to the directrix is given by c. This equation has its vertex at the origin (0, 0). If it opens to the left, the directrix is a vertical line to the right of the origin. This equation is y^2 = -4(1/2)x, so c = 1/2, and the directrix has the equation x = 1/2.
Part 3: The focus is inside the parabola, but it is the same distance from the vertex as the directrix. This distance is 1/2 units, and it will be to the left of the vertex. So the focus is at (-1/2, 0).
The correct option is fourth option
Explanations:
From the data, re-arranging in ascending order, the median of the data is 58.
The upper quartile is 62, while the lower quartile is 54
From the options, only the 4th options represent a box plot of median 58, upper quartile of 62 and lower quartile of 54. This makes it the correct option
Let's V the speed of the girl in step
v the speed of the escalator in step
L the length between ground and floor.
V*60+v*60=L ==> V+v=L/60
V*90-v*90=L ==> V-v=L/90
2V=L(3+2)/180
==>V=5L/360
Time to climb (in step) with v=0 (escalator standing still)
V*t=L==> t=L/V=L/(L*5/360)=72
The girl will count 72 steps.
The factors of the given expression are x , x - 2 and x - 4
So the expression for height and length are x and x - 4
The first consignment shows no association between the t-shirt size and the profit.
In the second consignment, the bigger the t-shirt size, the smaller the profit. There is an inverse relationship between the two variables.
In the third and fourth consignment, the bigger the size, the larger the profit. There is a direct relationship between the two variables.