Answer:
They'll reach the same population in approximately 113.24 years.
Step-by-step explanation:
Since both population grows at an exponential rate, then their population over the years can be found as:
For the city of Anvil:
For the city of Brinker:
We need to find the value of "t" that satisfies:
![\text{population brinker}(t) = \text{population anvil}(t)\\21000*(1.04)^t = 7000*(1.05)^t\\ln[21000*(1.04)^t] = ln[7000*(1.05)^t]\\ln(21000) + t*ln(1.04) = ln(7000) + t*ln(1.05)\\9.952 + t*0.039 = 8.8536 + t*0.0487\\t*0.0487 - t*0.039 = 9.952 - 8.8536\\t*0.0097 = 1.0984\\t = \frac{1.0984}{0.0097}\\t = 113.24](https://tex.z-dn.net/?f=%5Ctext%7Bpopulation%20brinker%7D%28t%29%20%3D%20%5Ctext%7Bpopulation%20anvil%7D%28t%29%5C%5C21000%2A%281.04%29%5Et%20%3D%207000%2A%281.05%29%5Et%5C%5Cln%5B21000%2A%281.04%29%5Et%5D%20%3D%20ln%5B7000%2A%281.05%29%5Et%5D%5C%5Cln%2821000%29%20%2B%20t%2Aln%281.04%29%20%3D%20ln%287000%29%20%2B%20t%2Aln%281.05%29%5C%5C9.952%20%2B%20t%2A0.039%20%3D%208.8536%20%2B%20t%2A0.0487%5C%5Ct%2A0.0487%20-%20t%2A0.039%20%3D%209.952%20-%208.8536%5C%5Ct%2A0.0097%20%3D%201.0984%5C%5Ct%20%3D%20%5Cfrac%7B1.0984%7D%7B0.0097%7D%5C%5Ct%20%3D%20113.24)
They'll reach the same population in approximately 113.24 years.
Answer:
Vp = 1 / 24 miles/min the speed in still water
Step-by-step explanation:
Lets call Vp speed of swimmer and Vw speed of water then:
Downstream Vp + Vw
Swimmer does 2 miles in 40 minutes then he does
1 mile in 20 minutes
Upstream Vp - Vw
Swimmer does 2 miles in 60 minutes then he does
1 mile in 30 minutes
We get the following system:
(Vp + Vw )* 20 = 1 (1) and
( Vp - Vw )* 30 = 1 (2)
Solving the system
From equation (1)
20*Vp + 20* Vw = 1 ⇒ Vw = ( 1 - 20*Vp ) /20
Plugging that value in the second equation
(Vp - Vw )* 30 = 1 ⇒ [ Vp - ( 1 - 20*Vp )/20 ] * 30 = 1
[20*Vp - 1 + 20*Vp ] * 30/20 = 1 ⇒ [ 40*Vp - 1 ] *30 = 20 or
[ 40*Vp - 1 ] *3 = 2
120* Vp - 3 = 2 ⇒ 120*Vp = 5 and Vw = 1 /120 miles/min
Vp = 5 / 120 miles/min or
Vp = 1 / 24 miles/min
and speed of water Vw = 1 / 120
A
substitute each point into the inequality and check validity of solution
A (4, 4)
4 ≤ 16 - 12 + 2 ⇒ 4 ≤ 6 → True hence valid solution
B (3, 3 )
3 ≤ 9 - 9 + 2 ⇒ 3 ≤ 2 → False hence not valid
C (1, 1 )
1 ≤ 1 - 3 + 2 ⇒ 1 ≤ 0 → False hence not valid
D (2, 2 )
2 ≤ 4 - 6 + 2 ⇒ 2 ≤ 0 → False hence not valid
Answer:
-13 < X < 13
Step-by-step explanation:
It is given |X| < 13.
Note that we have: |x| < a, for any real number 'a', then it equals:
-a < X < a.
So, in this case, |X| < 13 should be equal to -13 < X < 13.
Hence, the answer.
