Answer:
$52.44
Step-by-step explanation:
Long method:
1. Convert the percentage into a decimal (15/100 = 0.15)
2. Multiply the decimal by the cost of the haircut (0.15 x $45.60 = $6.84)
3. Add this product by the cost of the haircut ($6.84 + $45.60 = $52.44)
Quicker Way (easier w/ a calculator)
1. Add 100% to the percentage she wants to add (100% + 15% = 115%) You can also express this as a number (115/100 = 1.15)
2. Multiply this new percentage by the cost of the haircut (1.15 x $45.60 = 52.44)
In a single equation, it would be

A(n)=330 Plug in 10 for n
Number 1 is Rio Grande and number 2 is St. Lawrence River
Step-by-step explanation:
Answer:
A) 68.33%
B) (234, 298)
Step-by-step explanation:
We have that the mean is 266 days (m) and the standard deviation is 16 days (sd), so we are asked:
A. P (250 x < 282)
P ((x1 - m) / sd < x < (x2 - m) / sd)
P ((250 - 266) / 16 < x < (282 - 266) / 16)
P (- 1 < z < 1)
P (z < 1) - P (-1 < z)
If we look in the normal distribution table we have to:
P (-1 < z) = 0.1587
P (z < 1) = 0.8413
replacing
0.8413 - 0.1587 = 0.6833
The percentage of pregnancies last between 250 and 282 days is 68.33%
B. We apply the experimental formula of 68-95-99.7
For middle 95% it is:
(m - 2 * sd, m + 2 * sd)
Thus,
m - 2 * sd <x <m + 2 * sd
we replace
266 - 2 * 16 <x <266 + 2 * 16
234 <x <298
That is, the interval would be (234, 298)
Step-by-step explanation:
f(x) = 9 * 81^x
When x = -1/2,
f(-1/2) = 9 * 81^(-1/2) = 9 * (1/9) = 1.