Solve the equation check for extraneous solutions. 9 (9-8x) = 2x +3

Yesterday,Bethany sent 60 text messages. she said 15 percent of those messages were to her best friend. How many texts messages

dimulka [17.4K]

Answer:

9

Step-by-step explanation:

We have to multiply 60 by 15%

15% = $\frac{15}{100}$ = 0.15, hence

number of text = 60 × 0.15 = 9

7 0

3 years ago

Read 2 more answers

Which of the following is an integer?<br> 0.5<br> 1<br> 3/2

Vinil7 [7]

Yeah the answer is one

3 0

3 years ago

Read 2 more answers

How do you use proportions to solve percent problems

exis [7]

Answer:

Step-by-step explanation:

EXAMPLE #1:

What number is 75% of 4? (or Find 75% of 4.)

The PERCENT always goes over 100.

(It's a part of the whole 100%.)

4 appears with the word of:

It's the WHOLE and goes on the bottom.

A proportion showing one fraction with PART as the numerator and 4 as the denominator equal to another fraction with 75 as the numerator and 100 as the denominator.

We're trying to find the missing PART (on the top).

In a proportion the cross-products are equal: So 4 times 75 is equal to 100 times the PART.

The missing PART equals 4 times 75 divided by 100.

(Multiply the two opposite corners with numbers; then divide by the other number.)

4 times 75 = 100 times the part

300 = 100 times the part

300/100 = 100/100 times the part

3 = the part

A proportion showing the denominator, 4, times the diagonally opposite 75; divided by 100.

7 0

3 years ago

Curves:<br>) x2 + y2 + 3x + 5y - 18 = 0 at (1, 2);

Sergeeva-Olga [200]

Answer:

Hey, Something To help Check Out Symbolab its an online calc it has EVERYTHING thats how i do my math hope this helps

Step-by-step explanation:

3 0

3 years ago

34% of college students say they use credit cards because of the rewards program. You randomly select 10 college students and a

finlep [7]

Answer:

a) There is a 18.73% probability that exactly two students use credit cards because of the rewards program.

b) There is a 71.62% probability that more than two students use credit cards because of the rewards program.

c) There is a 82% probability that between two and five students, inclusive, use credit cards because of the rewards program.

Step-by-step explanation:

There are only two possible outcomes. Either the student use credit cards because of the rewards program, or they use for other reason. So, we can solve this problem by the binomial distribution.

Binomial probability

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

$P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}$

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

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

And $\pi$ is the probability of X happening.

In this problem, we have that:

10 student are sampled, so $n = 10$

34% of college students say they use credit cards because of the rewards program, so $\pi = 0.34$

(a) exactly two

This is P(X = 2).

$P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}$

$P(X = 2) = C_{10,2}.(0.34)^{2}.(0.66)^{8} = 0.1873$

There is a 18.73% probability that exactly two students use credit cards because of the rewards program.

(b) more than two

This is $P(X > 2)$ .

Either a value is larger than two, or it is smaller of equal. The sum of the decimal probabilities must be 1. So:

$P(X \leq 2) + P(X > 2) = 1$

$P(X > 2) = 1 - P(X \leq 2)$

In which

$P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2)$

So

$P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}$

$P(X = 0) = C_{10,0}.(0.34)^{0}.(0.66)^{10} = 0.0157$

$P(X = 1) = C_{10,1}.(0.34)^{1}.(0.66)^{9} = 0.0808$

$P(X = 2) = C_{10,2}.(0.34)^{2}.(0.66)^{8} = 0.1873$

$P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0157 + 0.0808 + 0.1873 = 0.2838$

$P(X > 2) = 1 - P(X \leq 2) = 1 - 0.2838 = 0.7162$

There is a 71.62% probability that more than two students use credit cards because of the rewards program.

(c) between two and five inclusive

This is:

$P = P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)$

$P(X = x) = C_{n,x}.\pi^{x}.(1-\pi)^{n-x}$

$P(X = 2) = C_{10,2}.(0.34)^{2}.(0.66)^{8} = 0.1873$

$P(X = 3) = C_{10,3}.(0.34)^{3}.(0.66)^{7} = 0.2573$

$P(X = 4) = C_{10,4}.(0.34)^{4}.(0.66)^{6} = 0.2320$

$P(X = 5) = C_{10,5}.(0.34)^{5}.(0.66)^{5} = 0.1434$

$P = P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.1873 + 0.2573 + 0.2320 + 0.1434 = 0.82$

There is a 82% probability that between two and five students, inclusive, use credit cards because of the rewards program.

6 0

3 years ago