95% of red lights last between 2.5 and 3.5 minutes.
<u>Step-by-step explanation:</u>
In this case,
- The mean M is 3 and
- The standard deviation SD is given as 0.25
Assume the bell shaped graph of normal distribution,
The center of the graph is mean which is 3 minutes.
We move one space to the right side of mean ⇒ M + SD
⇒ 3+0.25 = 3.25 minutes.
Again we move one more space to the right of mean ⇒ M + 2SD
⇒ 3 + (0.25×2) = 3.5 minutes.
Similarly,
Move one space to the left side of mean ⇒ M - SD
⇒ 3-0.25 = 2.75 minutes.
Again we move one more space to the left of mean ⇒ M - 2SD
⇒ 3 - (0.25×2) =2.5 minutes.
The questions asks to approximately what percent of red lights last between 2.5 and 3.5 minutes.
Notice 2.5 and 3.5 fall within 2 standard deviations, and that 95% of the data is within 2 standard deviations. (Refer to bell-shaped graph)
Therefore, the percent of red lights that last between 2.5 and 3.5 minutes is 95%
Answer:
The simplified form is: 
Step-by-step explanation:
To simplify the expression given we, need to open the brackets, and if there is power term. Then we need to group all the like terms and then arrange in the descending order of powers of the given expression.
Now the expression that is given to us is:

Here we will simplify it by grouping the like terms, as follows:

So this is the required simplified form.
Answer:
Infinitely Many Solutions
Step-by-step explanation:

2x + y = 1
2x - 2x + y = 1 - 2x
y = 1 - 2x
y = -2x + 1
4x + 2y = -1
4x + 2(-2x + 1) = -1
4x + 2(-2x) + 2(1) = -1
4x - 4x + 2 = -1
2 ≠ -1
The solution of the problem can't be a solution because they are both parallel lines, which means they have no solution.