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3 years ago

When 10 is added to half the sum of a number and 8, the result is 30. What is the number

2 answers:

5 0

Even though we don't know what the number is, we have to
give it some name, so that we have something to work with.

Now, 16 out of every 19 people will call the number ' X '.
But I like to call it ' M ' instead, for 'Mystery number'.

The mystery number . . . . . M
The sum of the number and 8 . . . M + 8
Half of that sum . . . . . . . . . . . . . . (1/2)(M + 8)
10 added to that sum . . . . . . . . . (1/2)(M + 8) + 10

You said that the result is 30, so I can write:

   (1/2) (M + 8) + 10 = 30

Now, subtract 10
from each side: (1/2) (M + 8) = 20

Multiply each side by 2 :     M + 8 = 40

Subtract 8 from
each side:    M = 32 .

Check to see if that's correct.
Take 32, and do everything to it that the question says:

The number . . . . . . . . . . 32 ?
The sum of the number and 8 . . . 32 + 8 = 40
Half of that sum . . . . . . . . . . . . . . (1/2)(40) = 20
10 added to that sum . . . . . . . . .   20 + 10 = 30

You said that the result is 30, and by golly IT IS !
So the mystery number is really 32.
yay !

Mekhanik [1.2K]3 years ago

4 0

10 + ( x+8 )/2 = 30

multiply all by 2
20 + ( x+8 ) = 60
x + 28 = 60
x = 32

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lisov135 [29]

Question 1: The y-intercept is where the line crosses the y-axis. The increments of the y-axis is by 20, and the y-intercept is at (0, 20).

The slope is the change in y over the change in x. Find two points:

(0, 20) and (2, 80)

Now:

(80 - 20)/(2 - 0) = 60/2 = 30

Slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept.

So:

y = 30x + 20

Question 2: Again, look for the y-intercept, which is pretty clear. It's (0, 60).

Now find two points:

(0, 60) and (2, 40)

Find the slope:

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ahrayia [7]

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__________________________

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3 years ago

The quotient of 100 and the quantity of 6+ Y

Butoxors [25]

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3 years ago

What is the sum of a 7-term geometric series if the first term is −11, the last term is −171,875, and the common ratio is −5?

mr_godi [17]

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4 0

3 years ago

Read 2 more answers

What is the value of q?

andre [41]

Answer: here

Step-by-step explanation:riangles QST and RST are similar. Therefore, the following is true:

q s

--- = ---- This results in 10q=rs.

r 10

Also, since RST is a right triangle, 4^2 + s^2 = q^2.

Since QST is also a right triangle, s^2 + 10^2 = r^2.

4 s

Also: ---- = ----- which leads to s^2 = 40

s 10

Because of this, 4^2 + s^2 = q^2 becomes 16 + 40 = 56 = q^2

Then q = sqrt(56) = sqrt(4)*sqrt(14) = 2*sqrt(14) (answer)

hope it helps

6 0

3 years ago