54 divided by four is 13.5 or 27/2
ANSWER

EXPLANATION
Since the directrix is

the axis of symmetry of the parabola is parallel to the y-axis.
Again, the focus being,

also means that the parabola will open upwards.
The equation of parabola with such properties is given by,

where

is the vertex of the parabola.
The directrix and the axis of symmetry of the parabola will intersect at

The vertex is the midpoint of the focus and the point of intersection of the axis of the parabola and the directrix.
This implies that,

and

The equation of the parabola now becomes,


Thus, the distance between the vertex and the directrix.
This means that,

Since the parabola opens up, we choose

Our equation now becomes,

This simplifies to

or

This is the same as,

The correct answer is D .
Answer:
12 3/20 is the simplest form
First brand = A, second brand = B.
A + B = 249ml
9% A + 14% B = 13% 249ml
B = 249ml - A
9% A + 14% (249ml - A) = 13% 249ml
9A + 14 (249ml - A) = 13 * 249ml
9A + 3486ml - 14A = 3237ml
5A = 249ml
A = 49,8ml
<span>B = 249ml - A = 199,2ml
</span>
Answer: He should use 49,8ml of first brand and 199,2ml of second brand.
Also note: <span>That's an </span>approximation,<span> because </span>the volumes are not strictly additive<span>. For example: mixing 50ml pure ethanol with 50ml water will give you about 95ml of mixture. To get an accurate answer, you'd have to </span>measure<span> the volume of the final mixture and then divide your total alcohol content by </span>that<span>.</span>