You need to understand that you're solving for the average, which you already know: 90. Since you know the values of the first three exams, and you know what your final value needs to be, just set up the problem like you would any time you're averaging something.
Solving for the average is simple:
Add up all of the exam scores and divide that number by the number of exams you took.
(87 + 88 + 92) / 3 = your average if you didn't count that fourth exam.
Since you know you have that fourth exam, just substitute it into the total value as an unknown, X:
(87 + 88 + 92 + X) / 4 = 90
Now you need to solve for X, the unknown:
87
+
88
+
92
+
X
4
(4) = 90 (4)
Multiplying for four on each side cancels out the fraction.
So now you have:
87 + 88 + 92 + X = 360
This can be simplified as:
267 + X = 360
Negating the 267 on each side will isolate the X value, and give you your final answer:
X = 93
Now that you have an answer, ask yourself, "does it make sense?"
I say that it does, because there were two tests that were below average, and one that was just slightly above average. So, it makes sense that you'd want to have a higher-ish test score on the fourth exam.
Answer:
option 2.
m1 = 75 , m2 = 129 , m3 = 100
Step-by-step explanation:
with the rule that the internal angles of a triangle add up to 180 ° we can calculate the missing angles
x + 46 + 29 = 180
x = 180 - 46 -29
x = 105
a flat angle has 180 °
m1 + 105 = 180
m1 = 180 - 105
m1 = 75
46 + 54 + y = 180
y = 180 - 46 -54
y = 80
80 = z + 29
z = 80 - 29
z = 51
as they are two crossed lines the angle is reflected from the opposite side
with that principle and knowing that the angle of a turn is 360 °, if we subtract the 2 known angles and divide it by 2 we will obtain the missing angle (m2)
m2 * 2 = 360 - 51 * 2
m2 = 258/2
m2 = 129
m2 = 29 + m3
129 = 29 + m3
m3 = 129 - 29
m3 = 100
<span>A = l x w
Since
l = 3w
Substitute the l with 3w
The formula will be
A = 3w + w
A = 4w
An example:
The
given known values are: Length of 4 cm Width is unknown Perimeter is 34
cm Find the dimensions of the rectangle. Since the geometric formula
for perimeter is: </span>
P= 2 (l + w)
L = 2w – 4 cm
W =?
Derivation and solution:
34 = 2 (2w - 4) + 2w <span>
34 = 4w – 8 + 2w</span>
42 = 6w 42/6 = w
W = 7 cm
34 = 2l + 2(7)
34 = 2l + 14
2l = 34 – 14
2l = 20
L = 20/2
L = 10 cm<span> <span>
</span></span>
Answer:
4990
Step-by-step explanation:
Multiply 638 by 5 then add 1800 and that's your answer
