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3 years ago

5.) Find the value: -2/3 - (-2/5) =

Mathematics

1 answer:

Citrus2011 [14]3 years ago

5 0

Answer: -4/15

Step-by-step explanation:

- 2/3 - (-2/5)

= -2/3 + 2/5

= -10/15 + 6/15

= -4/15

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Sarah is a computer engineer and manager and works for a software company. She receives a

daser333 [38]

Answer:

a) Number of projects in the first year = 90

b) Earnings in the twelfth year = $116500

Total money earned in 12 years = $969000

Step-by-step explanation:

Given that:

Number of projects done in fourth year = 129

Number of projects done in tenth year = 207

There is a fixed increase every year.

a) To find:

Number of projects done in the first year.

This problem is nothing but a case of arithmetic progression.

Let the first term i.e. number of projects done in first year = $a$

Given that:

$a_4=129\\a_{10}=207$

Formula for $n^{th}$ term of an Arithmetic Progression is given as:

$a_n=a+(n-1)d$

Where $d$ will represent the number of projects increased every year.

and $n$ is the year number.

$a_4=129=a+(4-1)d \\\Rightarrow 129=a+3d .....(1)\\a_{10}=207=a+(10-1)d \\\Rightarrow 207=a+9d .....(2)$

Subtracting (2) from (1):

$78 = 6d\\\Rightarrow d =13$

By equation (1):

$129 =a+3\times 13\\\Rightarrow a =129-39\\\Rightarrow a =90$

Number of projects in the first year = 90

b)

Number of projects in the twelfth year =

$a_{12} = a+11d\\\Rightarrow a_{12} = 90+11\times 13 =233$

Each project pays $500

Earnings in the twelfth year = 233 $\times$ 500 = $116500

Sum of an AP is given as:

$S_n=\dfrac{n}{2}(2a+(n-1)d)\\\Rightarrow S_{12}=\dfrac{12}{2}(2\times 90+(12-1)\times 13)\\\Rightarrow S_{12}=6\times 323\\\Rightarrow S_{12}=1938$

It gives us the total number of projects done in 12 years = 1938

Total money earned in 12 years = 500 $\times$ 1938 = $969000

8 0

2 years ago

Rewrite 40 1/4 as a decimal

Radda [10]

40.25 is 40 1/4 as a decimal

8 0

3 years ago

You guys, I seriously need help with this! I have been working on this for like 5 hours and I still can't understand it! Please

Alina [70]

Step-by-step explanation:

Q1. E

Q2. A

Q3. H

sorry if I'm wrong anyways

Q4. C

4 0

3 years ago

In circle o,find the value of x, rounded to the nearest tenth.

Gemiola [76]

Answer:

$\huge\boxed{x \approx 5.4}$

Step-by-step explanation:

We can break down this problem by first realizing different parts of the circle.

The line which is 8 units long is a chord of the circle.
The line that is 3.6 is almost the radius of the circle
The line that x sits on is the radius.

With this, we can find out if we find the radius of the circle, we have our answer.

We should also note that the angle formed by the 3.6 units long line and the chord is a right angle.

What we need is a way to find the radius of the circle. This will get us x. The radius of a circle will be the length of any line that starts from point O and ends at the circle edge.

If we draw a line connecting the end of the 3.6 line at point O to the end of the 8 unit long chord, we get a triangle! (Image attached for reference).

We can solve for the hypotenuse using the Pythagorean Theorem. This theorem states that:

$\displaystyle a^2 + b^2 = c^2$

Since we know one side is 3.6, we can use that as A. The second side will be 4 since the 3.6 line lies directly in the center of the chord = 8/2 = 4!

$3.6^2 + 4^2 = c^2$
$12.96+16=c^2$
$28.96=c^2$
$\sqrt{28.96} = c$
$5.4 \approx c$

Therefore, since this is the radius of the circle (also the hypotenuse), this can be said for any line that comes from point O onto the edge of the circle.

The line X does just that. Therefore, the value of x is also 5.4.

Hope this helped!

4 0

2 years ago

Three-fourths of the tickets had been sold, and there were 420 tickets left. How many tickets were printed?

Reil [10]

Answer:

Step-by-step explanation:

420 = 1/4 so 4/4 is 4 420s

420 x 4 = 1680

8 0

3 years ago

Read 2 more answers

5.) Find the value: -2/3 - (-2/5) =​

5.) Find the value: -2/3 - (-2/5) =