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3 years ago

There are 25 students in a class, 40 percent of whom are girls. If the average

Mathematics

1 answer:

svetoff [14.1K]3 years ago

5 0

Answer:

135

Step-by-step explanation:

120 + 150 = 270

270 ÷ 2 = 135

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Jessica is 5 years older than her sister Jenna. Jenna tells her sister that in 5 years, she will be as old as Jessica was 5 year

vlabodo [156]

Answer:

x + 5 = (x + 5) - 5, which has no solution ⇒ answer C

Step-by-step explanation:

* Lets study the situation in the problem

- Jessica is 5 years older than her sister Jenna

- After five years Jenna's age will be as old as Jessica was five years ago

- Jenna's age now is x

* Lets change all information above to equation

∵ Janna's age now is x

∵ Jessica is 5 years old than Janna

∴ The age of Jessica now is x + 5

- After 5 years Janna's age will be add by 5 years

∵ Her age now is x

∴ Her age after 5 years will be x + 5

- From 5 years ago Jessica's age was her age now mins 5 years

∵ Her age now is x + 5

∴ Her age from 5 years ago is (x + 5) - 5

∵ Janna's age after 5 years = Jessica age from 5 years ago

∴ x + 5 = (x + 5) - 5

- Lets solve the equation to know how many solution

∵ x + 5 = x + 5 - 5 ⇒ add the like terms

∴ x + 5 = x ⇒ subtract x from both sides

∴ 5 = 0

- But 5 ≠ 0, the two sides of the equation not equal each other

∴ There is no solution for this equation

* The equation is x + 5 = (x + 5) - 5, which has no solution

8 0

3 years ago

Read 2 more answers

cynthia has 32 pumpkins growing in her garden. twenty of them are ripe. what percentage of Cynthia's pumpkins are ripe

Mashutka [201]

Answer:

62.5

Step-by-step explanation:

8 0

3 years ago

Identify the range of the function shown in the graph.<br><br> help

amm1812

Answer:

-5 ≤ y ≤ 5

Step-by-step explanation:

maximum y value is 5

minimum y value is -5

-5 ≤ y ≤ 5

5 0

2 years ago

(cot^2x - 1)/(csc^2x) = cos2x

Alex787 [66]

Answer:

Step-by-step explanation:

The idea here is to get the left side simplified down so it is the same as the right side. Consequently, there are 3 identities for cos(2x):

$cos(2x)=cos^2x-sin^2x$ ,

$cos(2x)=1-2sin^2x$ , and

$cos(2x)=2cos^2x-1$

We begin by rewriting the left side in terms of sin and cos, since all the identities deal with sines and cosines and no cotangents or cosecants. Rewriting gives you:

$\frac{\frac{cos^2x}{sin^2x} -\frac{sin^2x}{sin^2x} }{\frac{1}{sin^2x} }$

Notice I also wrote the 1 in terms of sin^2(x).

Now we will put the numerator of the bigger fraction over the common denominator:

$\frac{\frac{cos^2x-sin^2x}{sin^2x} }{\frac{1}{sin^2x} }$

The rule is bring up the lower fraction and flip it to multiply, so that will give us:

$\frac{cos^2x-sin^2x}{sin^2x} *\frac{sin^2x}{1}$

And canceling out the sin^2 x leaves us with just

$cos^2x-sin^2x$ which is one of our identities.

5 0

3 years ago

3x^2+5x_=2+_

tatiyna

IT DOES NOT MATTER YOU WILL NOT BE ABLE TO SOLVE THIS QUESTION
YOU WOULD GET 5x = 2 + 3x^2 AND YOU WOULD STILL NOT BE ABLE TO SOLVE YOU COULD GET 3x^2 = 2 + 5x AND YOU COULD NOT SOLVE.
THE REASON WHY IS BECAUSE YOU HAVE TO HAVE THE SAME X TO ADD THEM OR MINUS THEM< WHICH IN THIS CASE ONE IS REGULAR BUT THE OTHER IS SQUARED. AND ALSO THE TWO NEEDS SOMEONE TO GO WITH< BUT THE IS ONLY ONE OF HIS TYPE SO HE CAN'T.
WELCOME :/

3 0

2 years ago