Given:
Nana has a water purifier that filters 
of the contaminants each hour.
Water has contaminants = 
To find:
The function that gives the remaining amount of contaminants in kilograms, C(t), t hours after Nana started purifying the water.
Solution:
Let C(t) be the remaining amount of contaminants in kilograms after t hours.
Initial amount of contaminants =
Decreasing rate is .
Using the exponential decay model:
where, 
is initial amount of contaminants, r is the decreasing rate and t is time in hours.
Substituting the values, we get
Therefore, the required function is .
39 foot into 3 pieces
one is 13 feet
the other pieces add up to the
remaining wire
which is 39-13=26 so
the two remaining pieces are x and y
one must be 2 less than 3 times the
other
x must be 2 less than 3 times the y
x=-2+3y
x=3y-2
x+y=remaining=26
26=x+y
x=3y-2
subsitute
26=3y-3+y
add like terms
26=4y-2
add 2 to both sides
28=4y
divide by 4
7=y
subsitute
7+x=26
subtract 7
x=19
19>7
7 feet is the legnth of the shorter
piece
Answer:
7
Step-by-step explanation:
7% of 100= 0.07
$300x0.07=$21
$300 of 7% sales tax is $21
$300+$21=$321 total purchase
Se puede viajar de Estados Unidos a España y regresar en una aerolínea diferente de 132 maneras posibles.
Dado que entre Estados Unidos y España hay 12 aerolíneas diferentes, para determinar de cuántas maneras se puede viajar de Estados Unidos a España y regresar en una aerolínea diferente se debe realizar el siguiente cálculo:
Por lo tanto, se puede viajar de Estados Unidos a España y regresar en una aerolínea diferente de 132 maneras posibles.
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