Answer:
Your number is -10
Hope this helps :)
Step-by-step explanation:
Let x be the number
Twice a number is 2x
Added to 7 means + 7 so 2x + 7
Is means =
2x+7=
At this point I have to assume you mean
"is the same as three subtracted from THE SAME number"
Otherwise, rather than a number, we end up with the
equation of a line....
2x + 7 = x - 3 subtract x from both sides
x + 7 = -3 subtract 7 from both sides
x = -10
Your number is -10
Check: 2x+7 = x-3
2(-10) + 7 = -10-3
-20+7 = -13
-13 = -13
The answer fits the parameters of the problem.
<em>a = 17</em>
<em>b = 18</em>
<em>c = 19</em>
- <em>Step-by-step explanation:</em>
<em>Hi there ! </em>
<em>a + b + c = 54</em>
<em>b = a + 1</em>
<em>c = a + 2</em>
<em>replace b ; c</em>
<em>a + (a + 1) + (a + 2) = 54</em>
<em>3a = 54 - 3</em>
<em>3a = 51</em>
<em>a = 51 : 3</em>
<em>a = 17</em>
<em>b = 18</em>
<em>c = 19</em>
<em>Good luck !</em>
Answer:
the answer is below
Step-by-step explanation:
The z score is used to calculate by how many standard deviations the raw score is above or below the mean. The z score is given as:

1) For x = 3

For x = 6

P(3 ≤ x ≤ 6) = P(-0.5 ≤ z ≤ 1) = P(z < 1) - P(z < -0.5) = 0.8413 - 0.3085 = 0.5328
2) For x = 50

For x = 70

P(50 ≤ x ≤ 70) = P(0.67 ≤ z ≤ 2) = P(z < 2) - P(z < 0.67) = 0.9772 - 0.7486 = 0.2286
3) For x = 8

For x = 12

P(8 ≤ x ≤ 12) = P(-2.19 ≤ z ≤ -0.94) = P(z < -0.94) - P(z < -2.19) = 0.1736 - 0.0143 = 0.1593
4) For x = 30

P(x ≥ 30) = P(z ≥ 2.94) = 1 - P(z < 2.94) = 1 - 0.9984 = 0.0016
5) x = 90

P(x ≥ 90) = P(z ≥ -0.67) = 1 - P(z < -0.67) = 1 - 0.2514 = 0.7486
6) For x = 10

For x = 20

P(10 ≤ x ≤ 20) = P(-1.25 ≤ z ≤ 1.25) = P(z < 1.25) - P(z < -1.25) = 0.8944 - 0.1056 = 0.7888
7) For x = 7

For x = 9

P(7 ≤ x ≤ 9) = P(1.67 ≤ z ≤ 3.33) = P(z < 3.33) - P(z < 1.67) = 0.9996 - 0.9525 = 0.0471
8) For x = 40

For x = 47

P(40 ≤ x ≤ 47) = P(-0.67 ≤ z ≤ -0.2) = P(z < -0.2) - P(z < -0.67) = 0.4207 - 0.2514 = 0.1693
9) x = 120

P(x ≥ 120) = P(z ≥ 7.33) = 1 - P(z < 7.33) = 1 - 0.9999 = 0.001
10) x = 2

P(x ≥ 2) = P(z ≥ -4) = 1 - P(z < -4) = 1 - 0.0001 = 0.999
Answer: the average speed of the runners increased since last year.
Step-by-step explanation:
The table is:
Mean MAD
Last Year 16.2 s 1.2
This Year 14.7 s 1.9
Looking at this table we can see that this year, the mean time is smaller than the one from last year, so the runners are faster in average.
The mean absolute deviation is bigger, but the change in the mean is bigger.
difference of the mean 16.2 - 14.7 = 1.5
difference of the MAD 1.9 - 1.2 = 0.7
This means that the average speed of the runners increased since last year, and the fact that the MAD increased means that not all the runners increased their speed at the same rate, so now the speeds of the different runners are not as alike like last year.