Answer: C 4
Step-by-step explanation:
Use the formula: distance = rate x time
We can say that train 1 travels a distance of x, and train 2 travels a distance of 700 - x
The rate of train 1 is 75 mph, and the rate of train 2 is 100 mph
The time traveled for the two trains will be the same. We can represent that with the variable t.
We have the following equation for train 1:
x = 75t
For train 2, we have this equation:
700 - x = 100t
Use the Substitution Method by replacing x in the equation for train 2 with the value 75t.
700 - 75t = 100t
700 = 175t
700/175 = 4 hours.
It will take 4 hours for the two trains to meet.
As an expression, it would be:
3 - 1/13w (or you could also do 1/13w - 3).
Answer: B. 3x + 1/5
tom's pencil is longer than Ellen's pencil:
5x + 2/5 - (2x + 1/5) = 5x - 2x + 2/5 - 1/5 = 3x + 1/5 (cm)
Step-by-step explanation:
Answer:
A
Step-by-step explanation:
So we have the piecewise function:

And we want to find f(8).
Since our input value is 8, choose the equation that fits our input.
The first equation demand x to be less than 3. 8 is not less than 3, so we won't use that.
The second equation demand x to e greater than or equal to 3 and less than 8. 8 is <em>not</em> less than 8. So, we won't use that.
The third equation demands x to be greater than or equal to 8. 8 is greater than or equal to 8, so we'll use the third equation.
So:


There're nothing more to do, we're done :)
The answer is A.
Edit: Improved Format
Answer:
16.5 year
Step-by-step explanation:
Using, mean = sum/no. *of observations
Here,
=> 16.2 = (sum of ages of boys)/18
=> 16.2 x 18 = sum of ages of boys
=> 291.6 = sum of ages of boys
Similarly, sum of ages of girls = 27 x 16.7 = 450.9
Mean(total) = (sumof agesof boys + girls)/45
Mean = (291.6 + 450.9)/45 = 16.5