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3 years ago

3. Lin had $18 in her bank account. She bought a ticket to the movies for

Mathematics

1 answer:

Elena-2011 [213]3 years ago

5 0

$9 + $7 + $5 = $21 so $18 - $21 = account balance = -$3

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The Pacific halibut fishery has been modeled by the differential equation dy dt = ky 1 − y K where y(t) is the biomass (the tota

Dafna1 [17]

Answer:

a. The biomass weighs 2.30 * 10^7 kg after a year

b. It'll take 2.56 years to get to 4*10^7kg

Step-by-step explanation:

k = 0.78,K = 6E7 kg

Given

dy/dt = ky(1- y/K)

Make ky dt the subject of formula

ky dt = dy/(1-y/K) --- make k dt the subject of formula

k dt = dy/(y(1-y/K))

k dt = K dy / y(K-y)

k dt = ((1/y) + (1/(K-y)))dy ---- integrate both sides

kt + c = ln(y/(K-y))

Ce^(kt) = y/(K-y)

Substitute the values of k and K

Ce^(0.78t) = y/(6*10^7 - y) ----- (1)

Given that y(0) = 2 * 10^7kg

(1) becomes

Ce^(0.78*0) = (2 * 10^7)/(6*10^7 - 2*10^7)

Ce° = (2*10^7)/(4*10^7

C = 2/7

Substitute 2/7 for C in (1)

2/7e^0.78t = y/(6*10^7 - y) ---(2)

We're to find the biomass a year later

So, t = 1

2/7e^0.78 = y/(6*10^7 - y)

0.62 = y/(6*10^7 - y)

y = 0.62(6*10^7 - y)

y = 0.62*6*10^7 - 0.62y

y + 0.62y = 0.62*6*10^7

1.62y = 0.62*6*10^7

1.62y = 3.72 * 10^7

y = 2.30 * 10^7kg.

Hence, the biomass weighs 2.30 * 10^7 kg after a year

Here, we're to calculate the time it'll take the biomass to get to 4*10^7 kg

Substitute 4*10^7 for y in (2)

2/7e^0.78t = 4*10^7/(6*10^7 - 4*10^7)

2/7e^0.78t = 4*10^7/2*10^7

2/7e^0.78t = 2

e^0.78t = (2*7)/2

e^0.78t = 2

t = 2 * 1/0.78

t = 2.56 years

Hence, it'll take 2.56 years to get to 4*10^7kg

8 0

3 years ago

The SAT mathematics scores in the state of Florida for this year are approximately normally distributed with a mean of 500 and a

Sergeeva-Olga [200]

Because it will be half2 standard deviation which will include 500-700.
2std will include from 300-700.
so it will be half of 95%.

7 0

3 years ago

Exercise 1.A committee of five people is chosen randomly from four men and six women. Find the probability that:a) Exactly four

MatroZZZ [7]

Answer with explanation:

Given : Number of men = 4

Number of women = 6

Total people = $6+4=10$

Total number of ways to make a committee of five people from 10 persons :-

$^{10}C_{4}=\dfrac{10!}{4!(10-4)!}=210$

a) Number of ways to make committee that has exactly four women :

$^6C_4\times ^4C_1=\dfrac{6!}{4!(6-4)!}\times4=60$

The probability that committee has exactly four women :

$\dfrac{60}{210}=\dfrac{2}{7}$

b) Number of ways to make committee that has at-least four women :

$^6C_4\times ^4C_1+^6C_5=\dfrac{6!}{4!(6-4)!}\times4+6=66$

The probability that committee at-least four women :

$\dfrac{66}{210}=\dfrac{22}{70}$

c) Number of ways that committee has more than 4 women :-

$^6C_5\times^4C_0=6$

The probability that committee has more than 4 women :-

$\dfrac{6}{210}$

Now, the probability that committee has at most four women :-

$1-\dfrac{6}{210}=\dfrac{204}{210}=\dfrac{102}{105}$

5 0

3 years ago

Pls help me with my math

Zinaida [17]

360 / 3 = 120
120 hamburgers • 2 = 240 hotdogs

6 0

3 years ago

The measure of two complementary angles are 2x degree and 3x degree, then value of x is

Lera25 [3.4K]

Answer:

2x+3x=90

or ,5x=90

or,x=90/5

X=18

3 0

2 years ago

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