She made the mistake in step 4
She should have divided by -2 not just 2 alone
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:
Y = 6 X=-1
Step-by-step explanation:
- Add the numbers 8x+-8x=0. 5y+y=6y. 22+14=36
- So that means 6y=36. So Y would equal 6
- Substitute the values it one of the original equations. 8x + 5(6) =22. 8x+30=22
- Minus 22 from both sides.
- That would give you 8x=-8
- So x would equal - 1
Answer:
52%
Step-by-step explanation:
13/25
There is no sum for this geometric series. it diverges rather than converges due to the absolute value of the common ratio (r), which is -3, being 3. for a geometric series to have a sum (to converge), the absolute value of r must be less than 1.
(you find r by dividing a2/a1, a3/a2, etc.)
hope this helps
