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3 years ago

An unknown number is multiplied by 3 and divided by -4. The result is -6.

Mathematics

1 answer:

harkovskaia [24]3 years ago

4 0

Answer:

x=8

Step-by-step explanation:

Let the unknown be x

3×x/-4=-6

Cross multiply

3x=24

Divide both sides by 3

x=8

Therefore the unknown number is 8

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Can someone help please, I need the answer

diamong [38]

Answer:

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Step-by-step explanation:

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3 0

3 years ago

9x +35=105x-72<br> Can you solve it?

Otrada [13]

I did my math on a piece of paper but the answer would be x= 107/96

3 0

3 years ago

A study indicates that 62% of students have have a laptop. You randomly sample 8 students. Find the probability that between 4 a

Scrat [10]

Answer:

72.69% probability that between 4 and 6 (including endpoints) have a laptop.

Step-by-step explanation:

For each student, there are only two possible outcomes. Either they have a laptop, or they do not. The probability of a student having a laptop is independent from other students. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

A study indicates that 62% of students have have a laptop.

This means that $n = 0.62$

You randomly sample 8 students.

This means that $n = 8$

Find the probability that between 4 and 6 (including endpoints) have a laptop.

$P(4 \leq X \leq 6) = P(X = 4) + P(X = 5) + P(X = 6)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 4) = C_{8,4}.(0.62)^{4}.(0.38)^{4} = 0.2157$

$P(X = 5) = C_{8,5}.(0.62)^{5}.(0.38)^{3} = 0.2815$

$P(X = 6) = C_{8,6}.(0.62)^{6}.(0.38)^{2} = 0.2297$

$P(4 \leq X \leq 6) = P(X = 4) + P(X = 5) + P(X = 6) = 0.2157 + 0.2815 + 0.2297 = 0.7269$

72.69% probability that between 4 and 6 (including endpoints) have a laptop.

3 0

3 years ago

A random sample of 35 undergraduate students who completed two years of college were asked to take a basic mathematics test. The

disa [49]

Answer:

The 90 % confidence limits are (-2.09, 8.09).

Since the calculated values do not lie in the critical region we accept our null hypothesis.

Step-by-step explanation:

The null and alternative hypothesis are given by

H0: σ₁²= σ₂² against Ha: σ₁² ≠ σ₂²

Confidence interval for the population mean difference is given by

(x`1- x`2) ± t √S²(1/n1 + 1/n2)

Where S ²= (n1-1)S₁² + S²₂(n2-1)/n1+n2-2

Critical value of t with n1+n2-2= 50+ 35-2= 83 will be -1.633

Now calculating

S ²=34* (12.8)²+ (14.6)²*49/83= 192.96

Now putting the values in the t- test

(75.1 -72.1) ± 1.633 √ 192.96(1/35 +1/50)

=3 ± 5.09

=-2.09, 8.09 is the 90 % confidence interval for the difference

The 90 % confidence limits are (-2.09, 8.09).

Since the calculated values do not lie in the critical region we accept our null hypothesis.

5 0

3 years ago

The polynomial given below has _____ root(s).

lisov135 [29]

3x²-8x+4=0
(3x-2) (x-2)=0
x=2/3 , x = 2
Hence, the polynomial has two positive roots.
Option A is the correct choice.

8 0

3 years ago