Solve by completing the square with working out -6x-x^2-8

All the fourth-graders in a certain elementary school took a standardized test. A total of 85% of the students were found to be

Aneli [31]

Answer:

There is a 2% probability that the student is proficient in neither reading nor mathematics.

Step-by-step explanation:

We solve this problem building the Venn's diagram of these probabilities.

I am going to say that:

A is the probability that a student is proficient in reading

B is the probability that a student is proficient in mathematics.

C is the probability that a student is proficient in neither reading nor mathematics.

We have that:

$A = a + (A \cap B)$

In which a is the probability that a student is proficient in reading but not mathematics and $A \cap B$ is the probability that a student is proficient in both reading and mathematics.

By the same logic, we have that:

$B = b + (A \cap B)$

Either a student in proficient in at least one of reading or mathematics, or a student is proficient in neither of those. The sum of the probabilities of these events is decimal 1. So

$(A \cup B) + C = 1$

In which

$(A \cup B) = a + b + (A \cap B)$

65% were found to be proficient in both reading and mathematics.

This means that $A \cap B = 0.65$

78% were found to be proficient in mathematics

This means that $B = 0.78$

$B = b + (A \cap B)$

$0.78 = b + 0.65$

$b = 0.13$

85% of the students were found to be proficient in reading

This means that $A = 0.85$

$A = a + (A \cap B)$

$0.85 = a + 0.65$

$a = 0.20$

Proficient in at least one:

$(A \cup B) = a + b + (A \cap B) = 0.20 + 0.13 + 0.65 = 0.98$

What is the probability that the student is proficient in neither reading nor mathematics?

$(A \cup B) + C = 1$

$C = 1 - (A \cup B) = 1 - 0.98 = 0.02$

There is a 2% probability that the student is proficient in neither reading nor mathematics.

6 0

3 years ago

A circle has a circumference of 44m. What

MakcuM [25]

<h3>Answer: B. 154 square meters</h3>

================================

Work Shown:

C = 44 is the circumference

in general, the circumference of a circle is

C = 2*pi*r

Plug in C = 44 and solve for r.

C = 2*pi*r

44 = 2*pi*r

2*pi*r = 44

r = 44/(2pi)

r = 7.0028175 which is approximate

--------------------

Now plug this into the formula for the area of a circle

A = pi*r^2

A = pi*(7.0028175)^2

A = 154.061985

A = 154 rounding to the nearest whole number

3 0

4 years ago

Read 2 more answers

The 20% tip on a $42 meal

blondinia [14]

Answer:

$8.4 hskshskshsjsjjsj

3 0

3 years ago

Julia is taking a test with multiple choice and true/false question the test has twentg question altogether . julia gets five po

Sonbull [250]

X=number of corect
y=number of incorrect
5 points for each correct so 5x
-1 point for each incorrect so -y

5x-y=76
solve for x and y

I like putting it into slope intercep tofrm which is y=mx+b
add y to both sides
5x=76+y
subtract 76 from both sides
5x-75=y
y=5x-76

subsitute values for x and get values for y
remember, that julia cannot answer a negative number of incorrect questions so y must be greater than or equal to 0

so solve for minimum
0<5x-76
add 76 to both sides
76<5x
divide by 5
15.2<x
you cannot answer a fraction of a correct quesiton so round up
16 is the minumum number of queswtions correctlyh answered

so
x>16

subsitute 16 for x
y=5(16)-76
y=80-76
y=4

as we subsitute more numbers over 16, we get these points
so (x,y)
(16,4)
(17,9)
(18,14)
(19,19)
(20,24)
(21,29)
(22,34)
(23,39)
x=correct answer
y=wrong answers

5 0

3 years ago

ILL MARK YOU BRAINLIEST

ryzh [129]

Answer:

-2.22, -√3, √9, π, 3.4

Step-by-step explanation:

Hope this helps :)

8 0

3 years ago