For
, we have
So for
to be continuous at
, we require that the limit as
is equal to 4.
Short Answer: 18 minutes
Remark
The answer to this problem is less than the smallest time of the two people working together. that fact lets out C and D (38 minutes and 75 minutes). Now you have to choose 15 minutes and 18 minutes. There's a method. No guessing needed.
Givens
Let the time for Sophie = S
Let the time for Simon = M
Let the job to completion = 1
S = 45 minutes
M = 30 minutes
Step One
Convert minutes to hours.
45 minutes = 45 / 60 = 3/4 hour = 0.75 hour
30 minutes = 30 / 60 = 1/2 hour = 0.50 hour
Step Two
Set up the Equation
The formula is a form of job / hour.
Let the time = t that they both have to work
job = 1 in these problems.
1/S + 1/M = 1/t
1/0.75 + 1/0.5 = 1/t
Solve
1 ÷ 0.75 = 1.33333
1 ÷ 0.5 = 2
1.3333 + 2 = 3.33333
3.3333 = 1 / t Multlply both sides by t
3.3333*t = 1
t = 1 / 3.333333333
t = 0.3 of an hour
1 hour = 60 minutes
0.3 hours = x Cross Multiply
x = 60 * 0.3
x = 18 minutes
Answer working together it took them 18 minutes <<<<<
Answer:
3x+2
Step-by-step explanation:
x+6/x+4+x-3/3
3x+6/4-3/3
3x+6/1/3
3x+6/3
3x+2
You can substitute what y is into the second equation, so:
3x + 4(2x + 1) = 26
3x + 8x + 4 = 26
11x + 4 = 26
- 4
11x = 22
÷ 11
x = 2
y = (2 × 2) + 1
y = 5 + 1
y = 5
So you get x as 2 and y as 5, I hope this helps!
Answer:
A
Step-by-step explanation:
Basically, this is an observational study because the researcher does not apply any treatment.
It's not an experiment because there is no experimentation involved. :)
It's not double-blind because in that case the researcher would have to apply something to two kinds of groups. one aware one the other not. not the case.
It's not D because The observations are comparing two kinds of subjects and they are not looking for a cause and effect.
