Answer: 15
REMEMBER: The mode is the value that appears most frequently in a data set.
<span>lets assume number of iphones sold = a
number of ipads sold = b
i sold 4 iphones more than ipad that becomes
a = b+4
then the equation of total commission becomes
30a+20b = 520
substituting a =b+4 in the above equation
30(b+4)+20b = 520
30b+120+20b = 520
50b =520-120
50b = 400
b = 400/50
b=8
number of iphones i sold = a = b+4 = 8+4 = 12
number of ipads i sold = 8
so i sold 12 iphones and 8 ipads to earn the commission of $520</span>
Part +part = whole
?+.5=4.6
4.6-0.5=4.1
rock A weighs 4.1 kilos
Answer:
y = (-1/19)(x - 8)² + 1521/76
Step-by-step explanation:
A parabola moves in such a way that it's distance from it's focus and directrix are always equal.
Now, we are given that directrix is y = 9.75 and focus is at (8, 0.25). Focus can be rewritten as (8, ¼) and directrix can be rewritten as y = 39/4
If we consider a point with the coordinates (x, y), it means the distance from this point to the focus is;
√((x - 8)² + (y - ¼)²)
Distance from that point to the directrix is; (y - 39/4)
Thus;
√((x - 8)² + (y - ¼)²) = (y - 39/4)
Taking the square of both sides gives;
((x - 8)² + (y - ¼)²) = (y - 39/4)²
(x - 8)² + y² - ½y + 1/16 = y² - (39/2)y + (39/4)²
Simplifying this gives;
(x - 8)² - (39/4)² = (½ - 39/2)y
(x - 8)² - 1521/4 = -19y
(x - 8)² - 1521/4 = -19y
Divide both sides by -19 to get;
y = (-1/19)(x - 8)² + 1521/76