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3 years ago

Solve A.12 + (-7) = b.-7 - 3 =

Mathematics

2 answers:

alisha [4.7K]3 years ago

7 0

Answer:

a. 5

b. -10

Step-by-step explanation:

i hope this helps :)

Alchen [17]3 years ago

5 0

Answer:

A) 5 B) -10

Step-by-step explanation:

A) 12-7 = 5

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at a country concert,the ratio of number of the Boys to the number of girls is 2:7 if there are 250 more girls than boys how man

sergey [27]

Answer:

100

Step-by-step explanation:

Ratio is a fraction, so ratio of boys to girls would be written as [let boys be "b" and girls be "g"]:

$\frac{b}{g}=\frac{2}{7}$

Also, there are 250 more girls than boys, so we can write:

g = 250 + b

Lets substitute this into "g" of the ratio we wrote and cross mulitply and solve for b:

$\frac{b}{g}=\frac{2}{7}\\\frac{b}{250+b}=\frac{2}{7}\\7b=2(250+b)\\7b=500+2b\\5b=500\\b=\frac{500}{5}=100$

The number of boys = 100

3 0

3 years ago

Suppose that the probability that any particle emitted by a radioactive material will penetrate a certain shield is 0.01. If 10

AnnyKZ [126]

Answer:

a)P=0.42

b) $n\geq 297$

Step-by-step explanation:

We have a binomial distribution, since the result of each experiment admits only two categories (success and failure) and the value of both possibilities is constant in all experiments. The probability of getting k successes in n trials is given by:

$P=\begin{pmatrix}n\\ k\end{pmatrix} p^k(1-p)^{n-k}=\frac{n!}{k!(n!-k!)}p^k(1-p)^{n-k}$

a) we have k=2, n=10 and p=0.01:

$P=\frac{10!}{2!(10!-2!)}0.01^2(1-0.01)^{10-2}\\P=\frac{10!}{2!*8!}0.01^2(0.99)^{8}\\P=45*0.01^2(0.99)^8=0.42$

b) We have, $1-(1-p)^n=P$ , Here P is the probability that at least one particle will penetrate the shield, this probabity has to be equal or greater than 0.95. Therefore, this will be equal to subtract from the total probability, the probability that the particles do not penetrate raised to the total number of particles.

$1-0.99^n\geq 0.95\\0.99^n\leq 1-0.95\\0.99^n\leq 0.05\\n\geq 297$

4 0

3 years ago

Sara takes 1/6 of an hour to vacuum his moms car it takes 4 times that long to wash the car then it takes you to wax the car twi

Nataly [62]

<h2>Answer:</h2><h2>2 hours & 10 minutes </h2><h2>Step-by-step explanation:</h2><h2>1/6 of an hour is 10 minutes. She vacuumed for 10 minutes. It took 4 times as long to wash the car so 10 * 4 = 40. She washed the car for 40 minutes. It took her twice as long to wax the car as it did for her to wash it so 40 * 2 = 80. She waxed the car for 80 minutes. 10 + 40 + 80 = 130 minutes or 2 hours and 10 minutes. </h2>

3 0

3 years ago

Find the arc length of the 3/4 of a circle with a radius of 5

IgorLugansk [536]

Answer:

7.5 pi

Step-by-step explanation:

The formula for arc length of a sector is denoted as

$\frac{x}{360}2\pi r$ , where x is the central angle of the sector.