1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kow [346]
3 years ago
11

80% of the students in Lea’s class earned an A or a B on the weekly math test. If 20 students got an A or a B, how many students

are in Lea’s class?
20 is 80% of what number?
20 × 4 = 80, so 100 × 4 = 400 students
20 + 60 = 80, so 100 + 60 = 160 students
80 ÷ 4 = 20, so 100 ÷ 4 = 25 students
80 – 60 = 20, so 100 – 60 = 40 students
Mathematics
2 answers:
blagie [28]3 years ago
8 0

Answer:

c

Step-by-step explanation:

Anna35 [415]3 years ago
6 0

Answer:

80 ÷ 4 = 20, so 100 ÷ 4 = 25 students

Step-by-step explanation:

Is means equals to  and of means multiply

20 = 80% * N

20 = .80 N

Divide each side by .8

20 / .8 = N

25 = N

there are 25 students

You might be interested in
he radioactive element​ carbon-14 has a​ half-life of 5750 years. A scientist determined that the bones from a mastodon had lost
elena-s [515]

Answer:

The bones were 12,485 years old at the time they were​ discovered.

Step-by-step explanation:

Amount of the element:

The amount of the element after t years is given by the following equation, considering the decay rate proportional to the amount present:

A(t) = A(0)e^{-kt}

In which A(0) is the initial amount and k is the decay rate, as a decimal.

The radioactive element​ carbon-14 has a​ half-life of 5750 years.

This means that A(5750) = 0.5A(0), and we use this to find k. So

A(t) = A(0)e^{-kt}

0.5A(0) = A(0)e^{-5750k}

e^{-5750k} = 0.5

\ln{e^{-5750k}} = \ln{0.5}

-5750k = \ln{0.5}

k = -\frac{\ln{0.5}}{5750}

k = 0.00012054733

So

A(t) = A(0)e^{-0.00012054733t}

A scientist determined that the bones from a mastodon had lost 77.8 ​% of their​ carbon-14. How old were the bones at the time they were​ discovered?

Had 100 - 77.8 = 22.2% remaining, so this is t for which:

A(t) = 0.222A(0)

Then

0.222A(0) = A(0)e^{-0.00012054733t}

e^{-0.00012054733t} = 0.222

\ln{e^{-0.00012054733t}} = \ln{0.222}

-0.00012054733t = \ln{0.222}

t = -\frac{\ln{0.222}}{0.00012054733}

t = 12485

The bones were 12,485 years old at the time they were​ discovered.

8 0
3 years ago
Find the value of x. Round to the nearest tenth.
Aliun [14]

Answer:

Step-by-step explanation:

Triangle XYZ is a right angle triangle.

From the given right angle triangle

XZ represents the hypotenuse of the right angle triangle.

With ∠34 as the reference angle,

YZ represents the adjacent side of the right angle triangle.

XY represents the opposite side of the right angle triangle.

To determine x, we would apply the Cosine trigonometric ratio

Cos θ = opposite side/hypotenuse. Therefore,

Cos 34 = x/28

x = 28Cos34 = 28 × 0.8290

x = 23.212

To the nearest tenth, it becomes

23.2

7 0
3 years ago
If you could answer all of these that would be very helpful please help!!
Vlad [161]
0.75 is equal to 6\8
5.8 is > 4\5
a decimal greater than 5\8 is 1.2
0.2 > 1\4
0.7>0.6
a decimal smaller than 6\8 is 0.01
The one that is not equal to -7\5 is -11\5 
The answer is D 

3 0
3 years ago
Ann is participating in a 4-day cross country biking challenge. She biked for 65, 69, and 45 miles on the first three days. How
GenaCL600 [577]

Answer:

the answer is 69

hope i helped <3

Step-by-step explanation:

6 0
2 years ago
Help!!! ASAP pleaseee!!
Alla [95]

Answer:

1. The two numbers are 4 and 8.

Step-by-step explanation:

1) variables: x and y

2) x + y = 12, y - x = 4

3) graph using desmos or another graphing calculator

4) the solution is x = 4, y = 8, or 4 and 8. This means that 4 and 8 can be added to equal 12, and the difference between them is 4.

5 0
3 years ago
Other questions:
  • Nayati wants to swim 50 miles this school year. She plans to swim 1/4 mile each day. How many days will it take her to swim 50 m
    10·1 answer
  • Total sales: $3546.95
    5·1 answer
  • Please do it fast......
    15·1 answer
  • The average rate of increase per year?
    13·1 answer
  • A rectangular flower bed has a length of 1/2 yard. The width of the flower bed is 3/4 yard. What is the area of the flower bed?
    10·1 answer
  • Find the probability of rolling an odd number on the first die and an even number on the second die
    11·1 answer
  • Pls answer dis quetsion
    9·1 answer
  • What side corresponds to AB?<br><br><br><br> LM<br> LN<br> MO<br> NO
    7·1 answer
  • If the point C is located at (5, 4) and C' is the image of C after being translated right 2. What are the
    5·1 answer
  • Which side lengths form an obtuse triangle? 0 28, 96, 100 O 40, 75, 85 O 17, 18, 19 O 2, 5,8 O 4, 5, 6
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!