Answer:
5
Step-by-step explanation:
We are given the geometric series:
-1, - 2, - 4, - 8.......
In the geometric series above, the common ratio = second term/first term = -2/-1
= 2
Where common ratio is greater than 1(r >1)
The sum of a geometric progression =
Sn = a(rⁿ -1)/r - 1
In the question we are asked to find the number of term = n
Sn = -31
a = -1
r = 2
Hence,
-31 = -1(2ⁿ - 1)/2 - 1
-31 = -1(2ⁿ - 1)
-31 = -2ⁿ + 1
2ⁿ = 1 + 31
2ⁿ = 32
2ⁿ = 2^5
n = 5
Therefore, the number of terms(n) = 5
A ratio shows us the number of times a number contains another number. Caitlin is right.
<h3>What is a Ratio?</h3>
A ratio shows us the number of times a number contains another number.
The ratio of the ages of Mandy and Sandy is 2:5. Therefore, the ratio will be,
M/S = 2/5
M = 2S/5
After 8 years, their ages will be in the ratio 1:2, therefore,
(M+8)/(S+8) = 1/2
2M + 16 = S + 8
2M - S = -16 + 8
Substitute the value of M,
2(2S/5) - S = -8
-0.2S = -8
S = 40
Now, if we substitute the value of S in the first ratio,
M/S = 2/5
M/40 = 2/5
M = 16
Now, if we take the difference in their ages the difference will be 24(40-16).
Since the difference is 24, we can conclude that Caitlin is right.
Hence, Caitlin is right.
Learn more about Ratios:
brainly.com/question/1504221
#SPJ1
Answer:
10%
Step-by-step explanation:
Answer:
Step-by-step explanation:
when 1/2 inch equals 4 feet the room is 2.25 inches, then
2 1/4 = 8/4 + 1/4 = 9/4
9/4 inches is the scale distance of the room
each 1/2 inch is 4 feet so divide 9/4 by 1/2 then multiply that by 4 to find the distance of the room
9/4 ÷ 1/2 = 9/4
9/4 * 2/1 = 18/4
18/4 = 9/2
9/2 * 4 feet = 9/2 * 4/1
9/2 * 4/1 = 36/2
36/2=18
the room is 18 feet across
then if the scale is 2/3 of an inch is 4 feet , then
2/3 * 9/4 = 18/12
18/12 = 3 inches is the scale size of Quinto's room
