Answer:
Step-by-step explanation:
The general formula for this sequence is a(n) = a(1)*(-1/4)^(n - 1). We don't yet know a(1).
If a(3) = 128, then 128 = a(1)*(-1/4)^(3 - 1), or
128 = a(1)*(1/16)
and so a(1) = 128/16
resulting in the specific formua a(n) = 8(-1/4)^(n - 1)
Now let's find a(7):
a(7) = 8(-1/4)^1 * (-1/4)^(6)
or
a(7) = 8(-1/4)^7
Complete Question
A set of magical wand prices are normally distributed with a mean of 50 dollars and a standard deviation of 4 dollars. A blackthorn wand has a price of 45.20. What proportion of wand prices are lower than the price of the blackthorn wand? You may round your answer to four decimal places
Answer:
0.1151
Step-by-step explanation:
We solve using z score formula
z = (x-μ)/σ, where
x is the raw score = $45.20
μ is the population mean = $50
σ is the population standard deviation = $4
We are solving for x < 45.20
Hence:
z = 45.20 - 50/4
z = -1.2
Probability value from Z-Table:
P(x<45.20) = 0.11507
Approximately to 4 decimal places = 0.1151
Therefore, the proportion of wand prices that are lower than the price of the blackthorn wand is 0.1151
Answer:6
Step-by-step explanation:solve the equation, you know that it equals 90 because the angle is 90
so 16x-6=90
+6 both sides
16x=96
divided by 16 both sides to isolate x
x=6
Answer:
1.25 gallons of alcohol
Step-by-step explanation:
Let x represent the amount of alcohol to add to the mix. Then the total amount of alcohol in the mix is ...
0.15×20 + x = 0.20×(20 +x)
3 +x = 4 + 0.2x . . . . simplify
0.8x = 1 . . . . . . . . . . add -3-0.2x
x = 1/0.8 = 1.25 . . . . divide by 0.8
1.25 gallons of alcohol should be added to make 21.25 gallons of 20% alcohol.
