Answer:
The average acceleration of train is 
Step-by-step explanation:
We have,
A train that slows down from 15 m/s to 8.6 m/s in 1.2 s. It means that 15 m/s is its initial velocity and 8.6 m/s is its final velocity.
It is required to find the average acceleration of the train.

The average acceleration of train is
. Negative signs shows that the train is decelerating.
The sphere. All the others are prisms.
We need to find out how many adults must the brand manager survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage.
From the given data we know that our confidence level is 90%. From Standard Normal Table we know that the critical level at 90% confidence level is 1.645. In other words,
.
We also know that E=5% or E=0.05
Also, since,
is not given, we will assume that
=0.5. This is because, the formula that we use will have
in the expression and that will be maximum only when
=0.5. (For any other value of
, we will get a value less than 0.25. For example if,
is 0.4, then
and thus,
.).
We will now use the formula

We will now substitute all the data that we have and we will get



which can approximated to n=271.
So, the brand manager needs a sample size of 271
Answer:
The average rate of change is 4.
Step-by-step explanation:
It is 4 because when you do the formula to find the rate of change it comes out to be 4.