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
sergejj [24]
2 years ago
6

The number of students at a high school was decreased by 30% to 420 after the senior students graduated how many students were a

t the high school before the decrease
Mathematics
1 answer:
olchik [2.2K]2 years ago
5 0

Answer:

Step-by-step explanation:

s(1-30/100)=420

s(100-30)/100=420

s(70/100)=420

s(7/10)=420

7s=4200

s=600

You might be interested in
How do you do this problem?
astra-53 [7]
By substitution is how to solve

2x-3y=21
y=3-x

2x-3(3-x)=21 
2x-9+3x=21
5x=30
x= 6

now substitute our x value into y=3-x
so we get 

y=3-6 = -3

so x=6 and y=-3  hope this helps!!!!! Thank you!
5 0
3 years ago
Read 2 more answers
Two cards are dealt at random from a standard deck of 52 cards. What is the probability that the first card is a King and the se
34kurt

Answer:

1 / 51

Step-by-step explanation:

Given that :

Number of cards in a deck = 52

Number of heart suit = 13

Number of kings = 4

Recall:

Probability = (required outcome / Total possible outcomes)

P(first card is king) = 4/52 = 1/13

P(second card is heart) = 13/51

Hence,

P(first card is king) * P(second card is heart)

(1/ 13) * (13/51) = 13 / 663 = 1/ 51

5 0
3 years ago
A simple random sample of 110 analog circuits is obtained at random from an ongoing production process in which 20% of all circu
telo118 [61]

Answer:

64.56% probability that between 17 and 25 circuits in the sample are defective.

Step-by-step explanation:

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

E(X) = np

The standard deviation of the binomial distribution is:

\sqrt{V(X)} = \sqrt{np(1-p)}

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that \mu = E(X), \sigma = \sqrt{V(X)}.

In this problem, we have that:

n = 110, p = 0.2

So

\mu = E(X) = np = 110*0.2 = 22

\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{110*0.2*0.8} = 4.1952

Probability that between 17 and 25 circuits in the sample are defective.

This is the pvalue of Z when X = 25 subtrated by the pvalue of Z when X = 17. So

X = 25

Z = \frac{X - \mu}{\sigma}

Z = \frac{25 - 22}{4.1952}

Z = 0.715

Z = 0.715 has a pvalue of 0.7626.

X = 17

Z = \frac{X - \mu}{\sigma}

Z = \frac{17 - 22}{4.1952}

Z = -1.19

Z = -1.19 has a pvalue of 0.1170.

0.7626 - 0.1170 = 0.6456

64.56% probability that between 17 and 25 circuits in the sample are defective.

4 0
3 years ago
Eight friends are going bowling together if they each rent a pair of bowling shoes for $2.00, they each play two
Mnenie [13.5K]

2.00+1.50= 3.50.

3.50x8= 28.00

I'm assuming they each paid 41.00 dollars for two games,

41.00x8= 328.00

328.00+28.00= $356.00

Hope this is correct and/or it helps!

Sorry, didn't realize my mistake.

4 0
3 years ago
Read 2 more answers
Question number 16 pls answer ​
lozanna [386]
3x - 6 = 4x + 1
3x - 6 + 6 = 4x + 1 + 6
3x = 4x + 7
3x - 4x = 4x + 7 - 4x

X = -7
:)
5 0
3 years ago
Read 2 more answers
Other questions:
  • What is the best estimate of the circumference of a circle with a diameter of 47 mm: a) 141mm b) 139mm c) 121mm d) 100mm
    6·1 answer
  • The angle measures are represented by algebraic expressions.
    13·1 answer
  • What is the answer to (4 x 3) х 10º =
    10·1 answer
  • Can someone help me, please?
    14·1 answer
  • What is the measure of the angle formed by the minute hand and hour hand of a clock in each case?
    6·1 answer
  • What happens when a home goes into foreclosure?
    10·1 answer
  • Write a quadratic equation whose solutions are 7i and -7i
    8·1 answer
  • How dose0.03 compare to0.003
    14·1 answer
  • A) If {3,1,-1,-3} is the range of the function f(x) =2x+3/5, find its domain.
    8·1 answer
  • 100(x - 3)=1000<br><br>can you help​
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!