<span> half life i= 78 hours
amount after 78 hours is 395 kg:
395 = 790e^(k*78)
Dividing by 790 and taking natural log
ln (395/790) = (k*78)
-0.6931 = 78k
-0.00888 = k
lets calculate how much is left after 18 hours:
Amount(18)
= 790e^(-0.00888*18)
Amount = 673.301 kg
hope this helps</span>
Answer: 
Step-by-step explanation:
Given: Sybil has 1/2 of a pizza left over.
If she share the pizza with 3 of her friends, to find the fraction of the original pizza will Sybil and her 3 friends each receive, we need to divide 1/2 by 3 we get
The fraction of the original pizza will Sybil and her 3 friends each receive

Answer:
a) x² +1
b) x² +25
Step-by-step explanation:
a) (x+i)(x− i)
= x² - ( i ) x + ( i ) x - ( i)²
= x² - i² ∵ i² = -1
= x² - (-1)
= x² +1
b) (x+5 i)(x− 5i)
= x² - ( 5 i ) x + ( 5 i ) x - ( 5 i)²
= x² - 25 i² ∵ i² = -1
= x² - 25(-1)
= x² +25
we can also solve
using identity
(a + b)(a - b) = a² - b²
= (x+5 i)(x− 5i)
= x² - (5 i)²
= x² - 25 i²
= x² +25
Respuesta:
(2945.411; 3054.589)
Explicación paso a paso:
Dado ;
Tamaño de la muestra, n = 50
Media, xbar = 3000
Desviación estándar, s = 200
Nivel de confianza, Zcrítico al 95% = 1,96
El intervalo de confianza se define como:
Xbar ± margen de error
Margen de error = Zcrítico * s / sqrt (n)
Margen de error = 1,96 * 200 / sqrt (50)
Margen de error = 54.589
Límite inferior = (3000 - 54.589) = 2945.411
Límite superior = (3000 + 54.589) = 3054.589
(2945.411; 3054.589)
Plug in the values
3(5) - 5(1)
15 - 5 = 10
Solution: 10