Which graph represents a positive linear association between x and y?
1 answer:
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x is 7.5 hours
Step-by-step explanation:
Ben, Tim, and Sam have to do a certain job
- Ben can finish the job in 5 hours
- Tim can finish the job in 6 hours
- Sam can finish the job in x hours
- The three of them can finish the job in 2 hours if they work together
We need to find x
∵ Ben can finish the job in 5 hours
∴ The rate of Ben =
∵ Tim can finish the job in 6 hours
∴ The rate of Tim =
∵ Sam can finish the job in x hours
∴ The rate of Sam =
They will working together to finish the job in two hours, that means the sum of their rate is equal to 1/2
∵ They can finish the job in 2 hours if they work together
∴
To add the fractions find the LCM for all denominators to make all fractions with same denominators
∵ The LCM of 5, 6 ans x is (5 × 6 × x) = 30 x,
- Divide it by each denominator to find the new numerators
∵ 30 x ÷ 5 = 6 x , 30 x ÷ 6 = 5 x , 30 x ÷ x = 30
- Change all the denominators to 30 x and then write the new
numerators of each fraction
∴
Add the numerators and put the sum over 30 x
∵
- By using cross multiplication
∴ 2(11 x + 30) = 1(30 x)
- Simplify the both sides
∴ 22 x + 60 = 30 x
- Subtract 22 x from both sides
∴ 60 = 8 x
- Divide both sides by 8
∴ 7.5 = x
∴ The value of x is 7.5 hours
x is 7.5 hours
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Answer:
112.569 ( D )
Step-by-step explanation:
Applying the estimated Regression Equation
y = b1X1 + b2X2 + a
b1 = ((SPX1Y)*(SSX2)-(SPX1X2)*(SPX2Y)) / ((SSX1)*(SSX2)-(SPX1X2)*(SPX1X2)) = 596494.5/635355.88 = 0.93884
b2 = ((SPX2Y)*(SSX1)-(SPX1X2)*(SPX1Y)) / ((SSX1)*(SSX2)-(SPX1X2)*(SPX1X2)) = 196481.5/635355.88 = 0.30925
a = MY - b1MX1 - b2MX2 = 149.25 - (0.94*61.31) - (0.31*193.88) = 31.73252
y = 0.939X1 + 0.309X2 + 31.733
For x1 ( age ) =39, and x2(weight) =143
y = (0.93884*39) + (0.30925*143) + 31.73252= 112.569
where
Sum of X1 = 981
Sum of X2 = 3102
Sum of Y = 2388
Mean X1 = 61.3125
Mean X2 = 193.875
Mean Y = 149.25
attached is the Tabular calculation of the required values needed for estimated regression equation
