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AlexFokin [52]
3 years ago
7

two years ago jenny was four times as old as helen. six years from now jenny will be twice as old as helen. how old are the girl

s now
Mathematics
2 answers:
vladimir1956 [14]3 years ago
7 0
Let Jenny's age (today) be J and Helen's age (today) be H We have the following equations: J-2 = (H-2)4J+6 = (H+6)2 Simplify J-2 = 4H-8J+6 = 2H+12 J=4H-6J=2H+6 Solve the system of equations by elimination -J=-4H+62J=4H+12 J=18 → plug into original equation → 18=4H-6 → 24=4H → H=6 We can check to verify if needed, but we will get that Jenny is 18 and Helen is 6 
Elina [12.6K]3 years ago
5 0
What  type of teacher would give a frustrating problem like this?!?
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A recipe for sparkling water juice calls for 1 1/2 quarts of sparkling water and 3/4 quart of grape juice
Alexxx [7]

Answer:

You would need 18 quarts of sparkling water to mix with 9 quarts of grape juice

Step-by-step explanation:

1 1/2 ---------> 3/4

x --------------> 9

We clear the value of x:

x = ((9) / (3/4)) * (1 1/2)

Rewriting we have:

x = ((9) * (4/3)) * (1 1/2)

x = (36/3) * (1 1/2)

x = (12) * (1 1/2)

x = (12) * (3/2)

x = 18

7 0
3 years ago
a street light is at the top of a 18 ft tall pole. a woman 6 ft tall walks away from the pole with a speed of 4 ft/sec along a s
shutvik [7]

The most appropriate choice for similarity of triangles will be given by -

Speed of tip of the shadow of woman  = 6 ft/s

What are similar triangles?

Two triangles are said to be similar, if the corrosponding angles of the triangles are same and the corrosponding sides of the triangles are in the same ratio.

Here,

The diagram has been attached here

Let the distance of woman from the pole be x ft and the distance of tip of the shadow to the pole be y ft.

Height of street light = 18 ft

Height of woman = 6ft

The two triangles are similar [As height of woman is parallel to the height of pole]

\frac{y - x}{6}=\frac{y}{18}\\18y - 18x = 6y\\18y - 6y = 18x\\12y = 18x\\y = \frac{18}{12}x\\y = \frac{3}{2}x\\

To find the speed, we have to differentiate both sides with respect to time 't'

\frac{dy}{dt} =\frac{3}{2}\frac{dx}{dt}\\\frac{dy}{dt}=\frac{3}{2} \times 4\\\frac{dy}{dt} = 6

Speed of tip of her shadow = 6 ft

To learn more about similarity of triangles, refer to the link-

brainly.com/question/14285697

#SPJ4

6 0
1 year ago
The probability that Brock scores a penalty kick is LaTeX: \frac{3}{10}3 10 . If he shoots 50 penalty kicks, how many "goals" ca
Feliz [49]

Answer:

15 goals out of 50 penalty kicks was scored by brock

Step-by-step explanation:

If Brock shoots 50 penalty kicks and the probability that he scores a penalty kick is 3/10, the number of goal brock is expected to make can be expressed as:

Number of goals scored = probability value * total penalty kicks taken

Number of goals scored = \frac{3}{10}*50

Number of goals scored = 15 goals

5 0
3 years ago
Which statement best describes the solution to this system of equations?
kondaur [170]

Answer:

x=-3

y=26

Step-by-step explanation:

3 0
3 years ago
The CPU of a personal computer has a lifetime that is exponentially distributed with a mean lifetime of six years. a) What is th
amm1812

Answer: Our required probability is 0.39.

Step-by-step explanation:

Since we have given that

X be the exponentially distributed with mean life = 6 years

So, E[x]=6

\dfrac{1}{\lambda}=6\\\\\lambda=\dfrac{1}{6}

So, our cumulative distribution function would be

F(x)=1-e^{-\lambda x}

We need to find the probability that the CPU fails within 3 years.

P(X

Hence, our required probability is 0.39.

7 0
3 years ago
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