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Tanya [424]
2 years ago
5

Bacteria begins to grow on the water's surface in a non-operational swimming pool on September 20. The bacteria grows and covers

the water's surface in such a way that the area covered with bacteria doubles every day. If it continues to grow in this way, the water's surface will be entirely covered with bacteria on September 28. When will a quarter of the water's surface be covered?
Mathematics
1 answer:
worty [1.4K]2 years ago
4 0

Working backwards, on Sept 27 the pool will be half covered, and on Sept 26 the pool will be one quarter covered.

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After getting 10% discount a customer paid RS 2034 with 13% VAT to buy a bag from a retailer. If the retailer made a profit of 2
german

Answer:

33.33%

Step-by-step explanation:

We are told that the customer paid Rs. 2034 after getting 10% discount with 13% vat on marked price (m.p.)

hence:-

2034 = m.p. × 90/100 × 113/100

m.p = (2034 × 100 × 100)/(90 × 113)

m.p. = Rs.2000

Now, due to the fact that VAT (which in this question is given to be 13%) is not the profit of the retailer, thus the selling price (s.p.) of the bag would be given by;

s.p = m.p. × 90/100

s.p = 2000 × 90/100

s.p = Rs. 1800

We are told that the retailer made a profit of 20%

Thus:-

c.p. × 120/100 = s.p.

c.p.= s.p. × 100/120

c.p.= 1800 × 100/120

c.p. = Rs.1500

Therefore, the percentage with which he marked above the c.p is;

% mark up = (m.p - c.p)/c.p) × 100

Plugging in the relevant values, we have;

(2000 - 1500)/1500) × 100

(500/1500) × 100 = 33.33%

7 0
2 years ago
What is the quotient? Negative StartFraction 3 over 8 EndFraction divided by negative one-fourth WILL GIVE BRAINLIEST
Alisiya [41]

Answer:

Im not too sure given yopur formatting, but I believe you meant this: -((3/8)/(-1/4))

therfore, the answer is: 3/2

Step-by-step explanation:

You can seperate the two fractions as 3/8 divided by -1/4, which is equal to 3/8 * 4/-1, simply multiply across to get 12/-8, which simplifies to -3/2. Flip the sign to get 3/2

3 0
2 years ago
A study is being conducted in which the health of two independent groups of ten policyholders is being monitored over a one-year
uysha [10]

Answer:

46.91% probability that at least nine participants complete the study in one of the two groups, but not in both groups

Step-by-step explanation:

We use two binomial trials to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

In which C_{n,x} is the number of different combinations of x objects from a set of n elements, given by the following formula.

C_{n,x} = \frac{n!}{x!(n-x)!}

And p is the probability of X happening.

Probability of at least nine participants finishing the study in a group.

0.2 probability of a students dropping out. So 1 - 0.2 = 0.8 probability of a student finishing the study. This means that p = 0.8.

10 students, so n = 10

We have to find:

P(X \geq 9) = P(X = 9) + P(X = 10)

Then

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 9) = C_{10,9}.(0.8)^{9}.(0.2)^{1} = 0.2684

P(X = 10) = C_{10,10}.(0.8)^{10}.(0.2)^{0} = 0.1074

P(X \geq 9) = P(X = 9) + P(X = 10) = 0.2684 + 0.1074 = 0.3758

0.3758 probability that at least nine participants complete the study in a group.

Calculate the probability that at least nine participants complete the study in one of the two groups, but not in both groups?

0.3758 probability that at least nine participants complete the study in a group. This means that p = 0.3758

Two groups, so n = 2

We have to find P(X = 1).

P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}

P(X = 2) = C_{2,1}.(0.3758)^{1}.(0.6242)^{1} = 0.4691

46.91% probability that at least nine participants complete the study in one of the two groups, but not in both groups

5 0
2 years ago
Read 2 more answers
Bruce wants to make 50 ml of an alcohol solution with a 12% concentration. He has a 10% alcohol solution and a
Ira Lisetskai [31]

Answer:

0.1x+0.15(50-x)= 50*0.12

Step-by-step explanation:

50 ml of 12% solution has 50*0.12 ml of alcohol

x ml of 10% solution has x*0.1 ml of alcohol

(50-x) ml of 15% solution has (50-x)*0.15 ml of alcohol

The equation to solve is:

  • 0.1x+0.15(50-x)= 50*0.12
3 0
2 years ago
Rubi tosses a quarter off the Main Street bridge into the St. John’s River. The distance, in feet, the quarter is above the wate
Masja [62]

Answer: a. 112 feet, b= 3 seconds, c= 256 feet, d = 6 seconds

Step-by-step explanation:

Here is the complete question:

Rubi tosses a quarter off the Main Street bridge into the St. John’s River. The distance, in feet, the quarter is above the water is modeled by the equation d(t) = −16t2+96t + 112, where t represents time in seconds.

Find the actual value(s) now to each question. Use the solution from the previous question to assist you with what you are actual solving for.

(a) From what height was the quarter tossed?

The quarter was tossed at 112 feet.

(b) How long does it take the quarter to reach its maximum height?

It will take ________ seconds for the quarter to reach its maximum height.

(c) What is the maximum height of the quarter?

The maximum height of the quarter is ________ feet.

(d) How much time does it take for the quarter to hit the water?

It will take ______ seconds for the quarter to hit the water.

a. Since the function is

d(t) = −16t² + 96t + 112,

The coin is tossed at 112 feet. This is because it is the the initial value of the function. It is the constant term and does not depend on any other variable.

b. To calculate the maximum height, we have to find vertex of the function, that has coordinates of h,k and,

h = -b/2a and k = f(h).

From the question, we are aware that,

a = -16, b = 96, c = 112

Using the values, the vertex will be:

h = -b/2a

= -96/(2 × -16)

= -96/-32

= 3

k = f(3)

= 16t² + 96t + 112

= -16(3)² + 96(3) + 112

= -144 + 288 + 112

= 256

The maximum height is therefore 256 feet, and time needed to reach the height will be 3 seconds.

c. The maximum height has been calculated and it is 256 feet.

d. The time it take for the quarter to hit the water will be:

= 3 seconds × 2 = 6 seconds

Since the maximum height took 3 seconds, it would take another 3 seconds to hit the water. This makes it 6 seconds

4 0
2 years ago
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