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The ratio of Wei Ling's age to Wei Xuan's age 5 years ago was 2: 5. In 9 years

Archy [21]

Answer:

15 years old

Step-by-step explanation:

Start by defining the variables that we are going to use throughout our working:

Let the current age of Wei Ling and Wei Xuan be L and X years old respectively.

Next, form equations using the given information.

5 years ago

Wei Ling: (L -5) years old

Wei Xuan: (X -5) years old

Given that the ratio of Wei Ling's age to that of Wei Xuan's is 2: 5,

$\frac{ L - 5}{X - 5} = \frac{2}{5}$

Cross multiply:

2(X -5)= 5(L -5)

Expand:

2X -10= 5L -25

2X= 5L -25 +10

2X= 5L -15 -----(1)

9 years time

Wei Ling: (L +9) years old

Wei Xuan: (X +9) years old

Given that the ratio of Wei Ling's age to that of Wei Xuan is 3: 4,

$\frac{L + 9}{X + 9} = \frac{3}{4}$

Cross multiply:

3(X +9)= 4(L +9)

Expand:

3X +27= 4L +36

3X= 4L +36 -27

3X= 4L +9 -----(2)

Let's solve using the elimination method.

(1) ×3:

6X= 15L -45 -----(3)

(2) ×2:

6X= 8L +18 -----(4)

(3) -(4):

6X -6X= 15L -45 -(8L +18)

0= 15L -45 -8L -18

0= 7L -63

7L= 63

L= 63 ÷7

L= 9

Substitute L= 9 into (1):

2X= 5(9) -15

2X= 45 -15

2X= 30

X= 30 ÷2

X= 15

Thus, Wei Xuan is 15 years old now.

6 0

2 years ago

A simple linear regression analysis was conducted to predict the Exam 3 score of students in STA 2023 based on their Exam 1 scor

Katena32 [7]

Answer:

Option A) As the Exam 1 score increases by 1 point, the student's Exam 3 grade will increase, on average, by 0.4845 points.

Step-by-step explanation:

We are given the following in the equation:

A simple linear regression analysis was conducted to predict the Exam 3 score of students in STA 2023 based on their Exam 1 score.

Thus, Exam 3 score becomes the dependent variable and exam 1 score is the independent variable.

The regression equation is given by:

$\hat{y} = 50.57+0.4845x$

Comparing the equation to a linear equation:

$y = mx + c$

m = 0.4845

c = 50.57

Where m is the slope and tells the rate of change and c is the y intercept that is the value of y when x is 0.

When, there is a increase in x, we can write:

$\hat{y}(x) = 50.57+0.4845x\\\hat{y}(x+1) = 50.57+0.4845(x+1)\\\hat{y}(x+1) - \hat{y}(x) = 50.57+0.4845(x+1)-(50.57+0.4845x)\\\hat{y}(x+1) - \hat{y}(x) = 0.4845$

Thus, the slope of equation can be interpreted as:

Option A) As the Exam 1 score increases by 1 point, the student's Exam 3 grade will increase, on average, by 0.4845 points.

5 0

3 years ago

A circle has a diameter of 10 centimeters. of a sector with a central angle of 50 degrees is cut out, what is the area of this s

kramer

Answer:

D. 10.91 square centimeters

Step-by-step explanation:

Area of a sector of a circle = $\frac{\theta}{360}\\$ $\pi$ $r^{2}$

where $\theta = 50^{o} C$

radius (r) = half of diameter = 10/2 = 5 cm

Area = $\frac{50}{360} * \frac{22}{7} * 5^{2}$

= 10.91 $cm^{2}$

8 0

3 years ago

What is the realationship between the volume of a cone and the volume of a sphere

patriot [66]

Depending on the size, the cone would have more volume

6 0

3 years ago

Ok so this is fraction what is 5/6 x 3/4

emmainna [20.7K]

Answer:

5/8

Step-by-step explanation:

6 0

3 years ago

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Need help will give brainlist​

Need help will give brainlist