Step-by-step explanation:
1. Oblicz:
a) Liczbę o 15% mniejszą od 60
b) Liczbę, której 15% stanowi 60
c) Jakim procentem 60 jest 15
d) O ile %większa jest 60 od 15
2. Kasia kupiła buty na wyprzedaży przecenione o 20%. Ich cena początkowa to 180 zł. W domu sprzedała je siostrze zarabiając na tym 10% wartości. Ile zapłaciła Kasi siostra za buty?
3. Liczba, którą powiększymy o 20% daje nam 30. Jaka to była liczba?
4. Za dwie książki zapłacono 42 zł. Ile kosztuje droższa z nich, jeżeli jedna jest o 25 % tańsza od drugiej?
A=Pe^(rt)
P = 800g
t = 8 years
A = 450g
r = This is what we will try and find to start with
450=800e^(r*8)
After running the math through a calculator, we end with r = -0.07192
Now we just re-input this information into our equation: A=800e^(-0.07192*16)
A=800e^(1.15072)
Now we will re-write the equation using the negative exponent rule:
A = 800 1/e^1.15072
Combine right side:
A = 800/e^1.15072
Then do the math:
A = 253.12709836......
That will give us A = 253 (rounded to the whole number)
I hope this helps! :)
No, it actually is not!
If you are to change it to a number,
14.5% = .145
Answer: 
Step-by-step explanation:
See attached image.
I have an expression

floating around in my head; let's see if it makes sense.
The variance of binary valued random variable b that comes up 1 with probability p (so has mean p) is

That's for an individual sample. For the observed average we divide by n, and for the standard deviation we take the square root:

Plugging in the numbers,

One standard deviation of the average is almost 2% so a 27% outcome was 3/1.9 = 1.6 standard deviations from the mean, corresponding to a two sided probability of a bit bigger than 10% of happening by chance.
So this is borderline suspect; most surveys will include a two sigma margin of error, say plus or minus 4 percent here, and the results were within those bounds.