Answer:
Step-by-step explanation:
Answer:
45
Step-by-step explanation:
Let the original number be xy where y is unit and x is tens hence original number is 10x+y When reversed, the new number is yz hence 10y+x
We know that the original number plus 9 is the reversed number hence
10x+y+9=10y+x
9y-9x=9 which when simplified we obtain that
y-x=1 equation 1
Originally, we are told that the sum of x and y is 9 hence
y+x=9 equation 2
Solving equation 1, it means y=x+1
Substituting the above into equation 2
x+1+x=9
2x=9-1
2x=8
x=8/2=4
Since y=x+1 then y=4+1=5
Therefore, the original number, xy is 45
Answer:
320 hope it helps :)
Step-by-step explanation:
Answer:
Correct option: b 39.
Step-by-step explanation:
A one-sample (or one mean) t-test is applied to test whether the population-parameter is significantly different from some hypothetical value.
The degrees of freedom of the <em>t</em>-test is:
df = n - 1
It is provided that the sample size is, <em>n</em> = 40.
Compute the degrees of freedom as follows:
df = n - 1
= 40 - 1
= 39
Thus, the correct option is b.
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➷ Simply substitute the values into the equations to see if it's correct:
Since the time taken will be more than 2 hours, we can try it with the value 3
t(x) = 70 + 5(3) = 85
g(x) = 30 + 15(3) = 75
As you can see, this is the incorrect choice as when a value more than 2 hours is used, the second engineer has a cheaper cost.
➶ Hope This Helps You!
➶ Good Luck (:
➶ Have A Great Day ^-^
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