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2 years ago

-2 < 3x+4 < 31 find x

Mathematics

1 answer:

Eva8 [605]2 years ago

8 0

First rewrite into 2 inequalities,

$-2\lt3x+4$

$3x+4\lt31$

Solve each of the inequalities,

$-2\lt3x+4\implies3x\gt-6\implies x\gt-2$

$3x+4\lt31\implies 3x\lt27\implies x\lt9$

So our x is between -2 and 9 which can be written as,

$-2\lt x\lt9$

or as an interval,

$x\in(-2,9)$

Hope this helps :)

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What is equal to 4y+y Thank you so much! Need an answer ASAP

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Answer:

Step-by-step explanation:

add like terms

since 4y and y are like terms you can add them to make 5y

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2 years ago

What is the area of a rectangle with vertices (2, 3), (9, 3), (9, Negative 2), and (2, Negative 2)?

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A racing car used 255 litres of fuel to complete a 340 km race.

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3 years ago

. A box in a certain supply room contains four 40-W lightbulbs, five 60-W bulbs, and six 75-W bulbs. Suppose that three bulbs ar

yaroslaw [1]

Answer:

a) 59.34%

b) 44.82%

c) 26.37%

d) 4.19%

Step-by-step explanation:

(a)

There are in total 4+5+6 = 15 bulbs. If we want to select 3 randomly there are K ways of doing this, where K is the combination of 15 elements taken 3 at a time

$K=\binom{15}{3}=\frac{15!}{3!(15-3)!}=\frac{15!}{3!12!}=\frac{15.14.13}{6}=455$

As there are 9 non 75-W bulbs, by the fundamental rule of counting, there are 6*5*9 = 270 ways of selecting 3 bulbs with exactly two 75-W bulbs.

So, the probability of selecting exactly 2 bulbs of 75 W is

$\frac{270}{455}=0.5934=59.34\%$

(b)

The probability of selecting three 40-W bulbs is

$\frac{4*3*2}{455}=0.0527=5.27\%$

The probability of selecting three 60-W bulbs is

$\frac{5*4*3}{455}=0.1318=13.18\%$

The probability of selecting three 75-W bulbs is

$\frac{6*5*4}{455}=0.2637=26.37\%$

Since the events are disjoint, the probability of taking 3 bulbs of the same kind is the sum 0.0527+0.1318+0.2637 = 0.4482 = 44.82%

(c)

There are 6*5*4 ways of selecting one bulb of each type, so the probability of selecting 3 bulbs of each type is

$\frac{6*5*4}{455}=0.2637=26.37\%$

(d)

The probability that it is necessary to examine at least six bulbs until a 75-W bulb is found, supposing there is no replacement, is the same as the probability of taking 5 bulbs one after another without replacement and none of them is 75-W.

As there are 15 bulbs and 9 of them are not 75-W, the probability a non 75-W bulb is $\frac{9}{15}=0.6$

Since there are no replacement, the probability of taking a second non 75-W bulb is now $\frac{8}{14}=0.5714$

Following this procedure 5 times, we find the probabilities

$\frac{9}{15},\frac{8}{14},\frac{7}{13},\frac{6}{12},\frac{5}{11}$

which are

0.6, 0.5714, 0.5384, 0.5, 0.4545

As the events are independent, the probability of choosing 5 non 75-W bulbs is the product

0.6*0.5714*0.5384*0.5*0.4545 = 0.0419 = 4.19%

3 0

3 years ago

2. Four less than six times a number is 32. Write and solve an equation.

zhenek [66]

Answer:

6x - 4 = 32. The variable (times a number) is equal to 6.

Step-by-step explanation:

So this equation is basically asking you to formulate an equation using only the words given. For this equation, let's use a variable in place of the part where it says "times a number." When a question says that phrase, that means that they are telling you to use a variable in place of a mystery number. A variable is a letter in place of a mystery number. Knowing this, let's now solve the equation. We will use the variable x in place of our mystery number.

Four less than 6 times a number: 6x - 4 _ __.

Now we can add the equal sign and the 32: 6x - 4 = 32.

We can now solve. Add 4 to both sides of the equation to cancel out the -4:

6x - 4 = 32

+4 + 4

6x = 36

Now we divide 6 into both sides of the equation to single out the x.

6x = 36

6 6

36/6 = 6, so:

x = 6

I hope that this helps.

8 0

2 years ago