First is to make equations for both sides.
Let x be the number of the miles.
a be the charge of the first company
b be the charge of the second
a=$35+$0.25(x), b=$40+$0.20(x) .
then a=b
Substitute the equations
$35+$0.25(x)=$40+$0.20(x)
$0.25x - $0.20x = $40 - $35
$0.05x = $5
x= $5/$0.05 , cancel out the unit.
x= 100
To justify substitute x to both the equations a and b.
a= 35 + 0.25(x)
a= 35 + 0.25(100)
a= 35 + 25
a= $60
b= 40 + 0.20(x)
b= 40 + 0.20(100)
b= 40 + 20
b= 60
a=b
60=60.
Given equation
Combine like terms
Addition or subtraction property of like terms
Multiplication or division of property of equality
Addition or subtraction property of like terms
And then your answer or (given equation I’m assuming
Okay, when rounding, always look at the number one place to the right, if it is five or above, round up, if it is below five, round down. 34.28 rounds to 34.3 in this case.
<span>Assuming the reaction is of 1st order, we can
start using the formula for rate of 1st order reaction:</span>
dN / dt = k * N
Rearranging,
dN / N = k dt
Where N = amount of sample, k = rate constant, t = time
Integrating the equation from N = Ni to Nf and t = ti to
tf will result in:
ln (Nf / Ni) = k (tf – ti)
Since k is constant, we can equate to situations.
Situation 1 is triple in size every days, situation 2 is after 20 days.
ln (Nf / Ni) / (tf – ti) = k
ln (3Ni / Ni) / 4 = ln (Nf / 40) / 20
Calculating for Nf,
<span>Nf =
9,720 bacteria </span>
