Step-by-step explanation:
P(t) = 12,000 (2)^(-t/15)
9,000 = 12,000 (2)^(-t/15)
0.75 = 2^(-t/15)
ln(0.75) = ln(2^(-t/15))
ln(0.75) = (-t/15) ln(2)
-15 ln(0.75) / ln(2) = t
t = 6.23
Answer:
15 square feet
Step-by-step explanation:
Multiply 1.5 by 3 which equals 4.5
Multiply 1.5 by 2 which equals 3
Add the above answers (4.5 plus 3)
Then multiply by 2 (7.5 times 2)
It equals 15
I hope this helps and that this is the right problem. There is no picture shown but I just did this problem for someone else so I thought I would take a shot at it :)
Well first you would start by setting up with a proportion.
In total, the girls paid $54+$22= $76
Thus 1 sister contributed $54/$76=x/100
The other sister contributed $22/$76=x/76
For each proportion, cross-multiply and simplify to get the percentage. The percentage will be the x
Answer:
A) 34.13%
B) 15.87%
C) 95.44%
D) 97.72%
E) 49.87%
F) 0.13%
Step-by-step explanation:
To find the percent of scores that are between 90 and 100, we need to standardize 90 and 100 using the following equation:

Where m is the mean and s is the standard deviation. Then, 90 and 100 are equal to:

So, the percent of scores that are between 90 and 100 can be calculated using the normal standard table as:
P( 90 < x < 100) = P(-1 < z < 0) = P(z < 0) - P(z < -1)
= 0.5 - 0.1587 = 0.3413
It means that the PERCENT of scores that are between 90 and 100 is 34.13%
At the same way, we can calculated the percentages of B, C, D, E and F as:
B) Over 110

C) Between 80 and 120

D) less than 80

E) Between 70 and 100

F) More than 130
