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:
around 230
Step-by-step explanation:
91+122+478=691
691÷3= 230.33333333
Answer:
The fraction is 
Step-by-step explanation:
= 
Where x and y are the numerator and denominator of our new fraction respectively.
Also given is that x + y = 24
So = 36 ÷ 60 = 0.6
x = 0.6y
Substituting x in x + y = 24 gives;
0.6y + y = 24 , 1.6y = 24
y = 24 ÷ 1.6 = 15
x = 24 - 15 = 9
So our fraction is
Answer:
David gets 28 more than Dan
Step-by-step explanation:
Jim: Dan : David: total
3 : 1 : 5 : 3+1+5 = 9
Jim gets 21
21/3 = 7
Multiply each number by 7
Jim: Dan : David: total
3*7 : 1*7 : 5 *7 : 9*7
21 : 7 : 35 : 63
David has 35 and Dan has 7
35-7 = 28
David gets 28 more than Dan
You do 390/100 = 180/x then 390×X=390X
180×100=18000
390X=18000
390X÷390=X
18000÷390=46.15384615=46%
