Answer:
See below
Step-by-step explanation:
From noon to 1500 is three hours
train A then travels <u> 3x</u> where x = speed in km/hr
train B only travels for 2.45 hours and covers
<u> 2.45 ( x + 15) </u> where x + 15 is its speed in km/hr
these two values sum to the 300 km distance
3x + 2.45 ( x + 15) = 300
3x + 2.45 x + 36.75 = 300
x = 48.3 km/hr x+15= 63.3 km / hr
Answer:
b
Step-by-step explanation:
Answer:
(-4, -1/2)
Step-by-step explanation:
to calculate the midpoints bt of the line use the ormula:
Where (x1, x2) is one coordinate point and (y1, y2) is anither coordinate point. Any two points will work, but I chose A (-5,-4) and B (-3, 3).
(-4, -1/2)
Answer:
x=4
Step-by-step explanation:
3(-4x+5)=12
3(-4x) + 3(5)=12
-12x+15=12
<u> -15</u><u>=-15</u>
-12x=-3
-x = -4
Since your x is negative change the signs
Answer:
The answer is false
Step-by-step explanation:
In a sample above 30 obs like this the confidence interval is defined as
X+- t* (s/sqrt(n)) where X is the mean t the tvalue for a given confidence level, n the size of sample and s standar deviation.
To find de appropiate value of t we must see the T table where rows are degrees of freedom and columns significance level
The significance is obtained:
significance = 1 - confidence level = 1 - 0.9 = 0.10
Degrees of freedom (df) for the inteval are
df = n - 1 = 18 - 1 = 17
So we must look for the value of a t with 17 values and significance of 0.10 which in t table is 1.740 not 1.746 ( thats the t for 16 df)
