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olchik [2.2K]
2 years ago
13

Twice jack’s age plus 5 is 21.write and solve an equation.how old is jack

Mathematics
1 answer:
Vedmedyk [2.9K]2 years ago
4 0

Answer:

  8

Step-by-step explanation:

If j represents Jack's age, we have ...

  2j +5 = 21

  2j = 16 . . . . . . subtract 5

  j = 8 . . . . . . . . divide by 2

Jack is 8 years old.

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Conditional Probability Assistance?
krek1111 [17]

Let the event A=\{ Sophomore \}, B=\{ Boy \}

The the probability of the events

P(A \cap B)=\frac{5}{12+18} =\frac{1}{6}

P( B)=\frac{12}{12+18} =\frac{2}{5}

The conditional probability

P(Sophomore|Boy)=P(A|B)=\frac{P(A \cap B)}{P(B)} =\frac{1/6}{2/5} =\frac{5}{12}

5 0
3 years ago
List all possible rational roots. Then use synthetic division to confirm which rational roots exist:
Kisachek [45]

Answer:

\boxed{(1) \, x = \, \pm \dfrac{1}{2}, \pm 1, \pm2, \pm \dfrac{5}{2}, \pm 5, \pm 10; (2) \, x = -2}

Step-by-step explanation:

2x³+ 6x² - x - 10 = 0

(1) Possible roots

The Rational Roots Theorem states that, if a polynomial has any rational roots, they will have the form p/q, where p is a factor of the constant term  and q is a factor of the leading coefficient.

\text{Possible rational root} = \dfrac{ p }{ q } = \dfrac{\text{factor of constant term}}{\text{factor of leading coefficient}}

In your function, the constant term is -10 and the leading coefficient is 2, so

\text{Possible root} = \dfrac{\text{factor of 10}}{\text{factor of 2}}

Factors of 10 = ±1, ±2, ±5, ±10

Factors of 2 = ±1, ±2

\text{Possible roots are } \large \boxed{\mathbf{x = \pm \dfrac{1}{2}, \pm 1, \pm2, \pm \dfrac{5}{2}, \pm 5, \pm 10}}

(2) Synthetic division

Rather than work through all 12 possibilities, I will do one that works.

\begin{array}{r|rrrr}-2 & 2 & 6 & -1 & -10\\& & -4& -4 & 10\\& 2 & 2& -5 & 0\\\end{array}

So, x = -2 is a root, and the quotient is 2x² + 2x - 5.

(3) Check for other rational roots

2x² + 2x - 5 = 0

D = b² - 4ac =2²- 4(2)(-5) = 4 + 40 = 44

√44 = 2√11, which is irrational.

Since irrational roots come in pairs, the cubic equation has two real, irrational roots and one rational root at x = -2.

6 0
4 years ago
Dalton's dad rode his bike 1 kilometer north,1 kilometer west,1 kilometer south,and 2 kilometer east.How many total kilometers w
Georgia [21]
1 + 1 + 1 + 2 = 5

5 x 9 = 45

Therefore, the total number of km is 45.
3 0
3 years ago
The mean incubation time of fertilized eggs is 23 days. Suppose the incubation times are approximately normally distributed with
Anna007 [38]

Answer: the incubation time that separates the bottom 2.5​% from the rest of the incubation times is 24.96 days.

Step-by-step explanation:

Suppose the incubation times are approximately normally distributed, we would apply the formula for normal distribution which is expressed as

z = (x - µ)/σ

Where

x = incubation times.

µ = mean time

σ = standard deviation

From the information given,

µ = 23 days

σ = 1 day

The probability value for the incubation time that separates the bottom 2.5​% from the rest of the incubation times would be (1 - 2.5/100) = (1 - 0.025) = 0.975

Looking at the normal distribution table, the z score corresponding to the probability value is 1.96

Therefore,

1.96 = (x - 23)/1

x = 1.96 + 23

x = 24.96

3 0
3 years ago
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How many 360 degree angles does it take to make a full turn?
lubasha [3.4K]
It needs only one 360 degree angle to make a full turn
It is also known as an angle at a point ..
6 0
3 years ago
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