It'd be easier to do #18 if y ou were to break it up:
14* (first term + 14th term)
Sum from n=1 to 14 of n = S = ---------------------------------
14 2
14(1+14)
= ---------------- = 7(15) = 105
2
The sum of twice that is 210. The sum of "1 from n=1 to n=14" is just 14.
The final sum is 210 + 14 = 224 (answer)
The power increases by 21% per hour. 21% written as a decimal is 0.21.
Because it increases you would multiply the starting value by 1.21 times the number of hours (t).
That needs to be less than or equal to 100,00
The equation would be:
C: 15,040(1.21)t ≤ 100,000
Dana can type 90 words per minute.
Since, 1 minute = 
hours
Therefore, number of words she can type = 
= 90×60
= 5400 words per hour
If she types 
words in 'x' hours.
Number of words Dana types with the given speed in 'x' hours = Speed of typing × Time
= 
Therefore, 
hours
Therefore, Dana types words in 48.15 hours.
Learn more,
brainly.com/question/621754
Answer:
plug n and r into the equation for the answers.
Step-by-step explanation:
