What is 30 minutes as a percentage of an hour?

Rewrite the following in the form log(c). log(10) – log(5)

Svet_ta [14]

Answer:

log(2)

Step-by-step explanation:

In order to combine log(10) and log(5), you need to look at the sign that's combining them. In this example, it is a subtraction sign. When two logs are being subtracting from each other, it's the same as dividing the two. You would rewrite it like this:

log(10/5)

You would then solve 10/5, and get 2. You would rewrite the log as:

log(2)

3 0

3 years ago

9. An article was sold at a profit of 12%. Had it been sold for Nu 80 more, there would be a profit of

Kamila [148]

Answer:

The cost price of the article was Nu 1,000

The original selling price was Nu 1,120

The second selling price was Nu 1,200

Step-by-step explanation:

System of Equations

Let's call:

x = Original selling price of the article

y = Cost of the article

The first condition implies that the difference between the selling price and the cost price (the profit) is 12%. Recall the profit % is always calculated with respect to the cost, that is, the profit at the first condition is:

0.12y = Original profit

Setting up the equation, we have:

$x-y=0.12y$

The second condition states the selling price is 80 Nu more than before, that is:

x+80= Second selling price of the article

y = Cost of the article (it doesn't change)

The profit of this condition is 20%, thus:

0.2y = Second profit

This produces a second equation:

$x+80-y=0.2y$

Let's put both equations together to form a system of equations:

$x-y=0.12y$

$x+80-y=0.2y$

Operating on both equations:

$x=1.12y$

$x=1.2y-80$

Equating both equations, we have an equation with only y's:

$1.12y=1.2y-80$

Subtracting 1.2y on each side:

$1.12y-1.2y=-80$

Operating:

$-0.08y=-80$

Solving:

$\displaystyle y=\frac{-80}{-0.08}=1,000$

a)

The cost price of the article was Nu 1,000

b) The selling price of the article will be calculated in both cases:

Original selling price: x=1.12y= 1.12*1000=1,120

The original selling price was Nu 1,120

The second selling price was x+80=1,200

The second selling price was Nu 1,200

8 0

3 years ago

A positive real number is 2 less than another. When 4 times the larger is added to the square of the smaller, the result is 49.

Kobotan [32]

Answer:

The numbers are

$-2+3\sqrt{5}$ and $3\sqrt{5}$

Step-by-step explanation:

Let

x -----> the smaller positive real number

y -----> the larger positive real number

we know that

A positive real number is 2 less than another

so

$x=y-2$

$y=x+2$ ----> equation A

When 4 times the larger is added to the square of the smaller, the result is 49

so

$4y+x^2=49$ ----> equation B

substitute equation A in equation B

$4(x+2)+x^2=49$

solve for x

$x^2+4x-41=0$

The formula to solve a quadratic equation of the form

$ax^{2} +bx+c=0$

is equal to

$x=\frac{-b\pm\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$x^2+4x-41=0$

so

$a=1\\b=4\\c=-41$

substitute in the formula

$x=\frac{-4\pm\sqrt{4^{2}-4(1)(-41)}} {2(1)}$

$x=\frac{-4\pm\sqrt{180}} {2}$

$x=\frac{-4\pm6\sqrt{5}} {2}$

$x=-2\pm3\sqrt{5}$

so

The positive real number is

$x=-2+3\sqrt{5}$

Find the value of y

$y=x+2$

$y=-2+3\sqrt{5}+2$

$y=3\sqrt{5}$

6 0

3 years ago

What is -9+n/4=-7? Please explain in detail, I don’t really understand this at all.

Brrunno [24]

Answer:

n=-19

Step-by-step explanation:

-9+n/4=-7

Multiply 4 on both sides

-9+n=-28

Add 9 on both sides

n=-19

5 0

3 years ago

What is 2/5 divided by 5/7 in fraction form, not decimal

PIT_PIT [208]

Ok. In order to do this set up 2/5 divided by 5/7. The way you divide with fractions is by multiplying them but flipping the second fraction into 7/5 <---this is known as the reciprocal. In other words do:

2/5 x 7/5 =
14/25
There you go.

6 0

3 years ago