Answer:
66
Step-by-step explanation:
Use the formula for the mean of a set of numbers:
sum of the numbers
average = --------------------------------
count of numbers
Here we know that the average mark was 68, so we can write:
75 + 62 + 84 + 53 + x
average = 68 = ----------------------------------
5
or 274 + x
68 = -------------------
5
Solving for x, we multiply both sides by 5: 340 = 274 + x.
Subtracting 274 from both sides effectively isolates x:
340 = 274 + x
- 274 -274
------------------------
66 = x
The fifth student's mark was 66.
Answer:
B, C
Step-by-step explanation:
The only statements that must be true are ones that describe the markings on the diagram:
NO as an angle bisector
N is the vertex of a pair of congruent angles
_____
The only other fact that must be true is that segments on the left side of the diagram are proportional to those (corresponding) on the right. (This is a property of the angle bisector.) There is nothing that says the sides must be equal, or that the triangle is isosceles.
Using how tall it is over how wide
=>tall/wide
The model 15in/1.5in
The actual x/55ft
Convert everything into the same units so 55ft to inches
There are 12in in 1ft
55ft * 12in/1ft
The ft cross out leaving in
55*12in= 660 in
So
15in/1.5in = x/660in
Now solve for x my multiplying both side by 660in
660in *15in/1.5in=x
x= 6600in tall
Y=4x+1
Let y=0
0=4x+1
4x=-1
x=-1/4
Let x=0
Y=4*0+1
Y=0+1
Y=1
Therefore, the ordered pair is (-1/4, 1)
