Using the mean concept, it is found that on average, it takes him 11.9 seconds to run a 100 yard dash.
<h3>What is the mean?</h3>
The mean of a data-set is given by the <u>sum of all observations in the data-set divided by the number of observations</u>.
In this problem, the three observations are given by:
12.7 s, 11.2 s, 11.8 s.
Hence the mean is:
M = (12.7 + 11.2 + 11.8)/3 = 11.9.
On average, it takes him 11.9 seconds to run a 100 yard dash.
More can be learned about the mean of a data-set at brainly.com/question/24628525
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Answer:
- 11 or - 15
Step-by-step explanation:
Factorise
x² - 13x + 42
Consider the factors of the constant term (+ 42) which sum to give the coefficient of the x- term (- 13)
The factors are - 6 and - 7, since
- 6 × - 7 = + 42 and - 6 - 7 = - 13, thus
x² - 13x + 42 = (x - 6)(x - 7)
compare to (x + A)(x + B)
A = - 6, B = - 7
thus 3A - B = 3(- 6) - (- 7) = - 18 + 7 = - 11
The factors may also be expressed as (x - 7)(x - 6)
with A = - 7 and B = - 6, then
3A - B = 3(- 7) - (- 6) = - 21 + 6 = - 15
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