Answer:
Let the speed of the train be x km/h.
Case 1:
Distance = 288 km
Speed = x km/h
Time = Distance/Speed
= 288/x h
Case 2:
Distance = 288 km
Speed = (x+4) km/h
Time = 288/x + 4 h
Since 288/x > 288/x + 4
288/x - 288/x+4 = 1
288[1/x - 1/x+4 ] = 1
[ x + 4 - x / x(x + 4) ] = 1/288
[4 / x^2 + 4x ] = 1/288
x^2 + 4x = 1152
x^2 + 4x - 1152 = 0
x^2 + 36x - 32x - 1152 = 0
x(x + 36) - 32(x + 36) = 0
(x + 36)(x - 32) = 0
x + 36 = 0 , x - 32 = 0
x = -36 , x = 32
x = -36 , rejected since speed cannot be negative.
Therefore , speed of the train = 32 km/h
Answer:
$24
Step-by-step explanation:
You simply do $42-$18
=24
2x + 12 = 18
18 - 12 = 6
2x = 6
x = 3
Answer:
The graph in the attached figure
Step-by-step explanation:
we have
Remember that the denominator cannot be equal to zero
so
The value of x cannot be equal to x=-2
<em>Simplify the numerator</em>
----> by difference of squares
substitute
simplify
The domain is all real numbers except the value of x=-2
The y-intercept is the point (0,-6) ---> value of y when the value of x is equal to zero)
The x-intercept is the point (2,0) ---> value of x when the value of y is equal to zero)
therefore
The graph in the attached figure
Answer:
b. There's no statistically significant linear relationship between the number of miles driven and the maintenance cost
Step-by-step explanation:
The p-value for the slope estimate show us how strong is the certainty that there are a linear relationship between both variables. In this case, the p-value for the slopes shows if there is a significant relationship between the number of miles driven and the maintenance cost.
If we have a high p-value like 0.7 we can said that there is no certainty in the linear relationship. it means that there's no statistically significant linear relationship between the number of miles driven and the maintenance cost.
