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.
<u>5 years </u><u>ago</u>
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,
Cross multiply:
2(X -5)= 5(L -5)
Expand:
2X -10= 5L -25
2X= 5L -25 +10
2X= 5L -15 -----(1)
<u>9 years time</u>
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,
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.
Answer:
3x^2 + 10x
Step-by-step explanation:
Answer:
P(Dᶜ )=0.41
Step-by-step explanation:
In the survey, the event D is the event of people who prefer to flirt directly in person.
Given that P(D)=0.590.
If someone is selected randomly, the probability that the individual prefers to flirt directly in person is 0.590.
If the person does not like to flirt in person, the probability of it will be the complement of event D.
From Probability Theory,
P(D)+P(Dᶜ )=1
0.590+P(Dᶜ )=1
P(Dᶜ )=1-0.590=0.41
The probability that the selected person does not like to flirt in person is 0.41.
The direct variation equation relates x and y is y = x
Step-by-step explanation:
Direct variation is when one variable is equal to a constant times another variable
If y varies directly with x, then
- y ∝ x
- y = k x is the equation of variation
- k is the constant of variation
∵ y varies directly with x
∵ y ∝ x
∴ y = k x
∵ y = 10 when x = 3
- Substitute these values in the equation above to find k
∴ 10 = k(3)
∴ 10 = 3 k
- Divide both sides by 3
∴ k =
∴ The equation of variation is y = x
The direct variation equation relates x and y is y = x
Learn more:
You can learn more about variation in brainly.com/question/10708697
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A. I took a educated guess