Answer:
B. 0.65
Step-by-step explanation:
Sample proportion is the point estimate of the population proportion which is at the centre of the interval
(0.62+0.68)/2
1.30/2
0.65
Set up two equations:
1st: P (for Price family) + J (for Jenkins family) = 45 hours
2nd: 20P + 35J = 1200 liters
Rewrite the first equation as P = 45 – J
Replace P in the second equation:
20(45-J) + 35J = 1200
Simplify:
900 -20J + 35J = 1200
900 +15J = 1200
Subtract 900 from both sides:
15J = 300
Divide both sides by 15:
J = 300/15
J = 20
Jenkins used theirs for 20 hours
Price used theirs for 45-20 = 25 hours.
1) y= - 2x² + 8x. It's a parabola open downward (a<0)
2) x - 2.23.y + 10.34 = 0 . Re-write it : y = (x/2.23) + (10.34/2.23), a linear equation.
To find the intersections between 1) & 2), let 1) = 2)
-2x² + 8x = (x/2.23) + (10.34/2.23)
-2x² + 8x - (x/2.23) - (10.34/2.23) =0 ; solve this quadratic for x values:
x' (that is A) = 0.772 & x" (that is B) = 3. (these are the values of x-intercept (parabola with line). To calculate the y-values, plug x' & x' in the equation:
for x' = 0.772, y = 0.34 → B(0.772 , 0.34)
for x" = 3, y = 0.016 → A(3 , 0.O16)
So B IS AT 0.34 Unit from the ground
