Let's solve for "r" by bringing them all to one side.
-3r=6-4r
+4r +4r
r=6
So, r is equal to 6.
The nth term of the geometric sequence is:
an=ar^(n-1)
where
a=first term
r=common ratio
n=nth term
from the question:
120=ar(3-1)
120=ar^2
a=120/(r^2)....i
also:
76.8=ar^(5-1)
76.8=ar^4
a=76.8/r^4.....i
thus from i and ii
120/r^2=76.8/r^4
from above we can have:
120=76.8/r²
120r²=76.8
r²=76.8/120
r²=0.64
r=√0.64
r=0.8
hence:
a=120/(0.64)=187.5
therefore the formula for the series will be:
an=187.5r^0.8
Answer:
79.95
Step-by-step explanation:
The first step is to rewrite the percentages into decimals so they can be added or subtracted easier. To turn a percentage into a decimal, remove the percent sign and move the decimal two spaces to the left (in other words, divide the number by 100).
12% becomes -0.12
8% becomes 0.08
Now, let's solve.
79.99 - 0.12 + 0.08
Evaluating 79.99 - 0.12, the equation becomes 79.87 + 0.08.
Evaluating 79.87 + 0.08, we get the final answer, 79.95.
9514 1404 393
Answer:
A) 29/40
Step-by-step explanation:
The formula for this is ...
P(A or B) = P(A) + P(B) - P(A and B)
Filling in the given values, you have ...
P(A or B) = 9/20 +1/2 - 9/40
P(A or B) = 18/40 +20/40 -9/40 = (18+20-9)/40
P(A or B) = 29/40 . . . . matches choice A
