So you know the merchant made a 15% profit on the pen, so she bought it for a cheaper price. To find the cost of the pen before you have to take the price now, $6.90 and times it by 85%. You do 85% because you subtract the 15% she saved from 100% and you get 85%. So 6.90x.85= 5.865 which rounds to $5.87
Answer:
A. E(x) = 1/n×n(n+1)/2
B. E(x²) = 1/n
Step-by-step explanation:
The n candidates for a job have been ranked 1,2,3....n. Let x be the rank of a randomly selected candidate. Therefore, the PMF of X is given as
P(x) = {1/n, x = 1,2...n}
Therefore,
Expectation of X
E(x) = summation {xP(×)}
= summation {X×1/n}
= 1/n summation{x}
= 1/n×n(n+1)/2
= n+1/2
Thus, E(x) = 1/n×n(n+1)/2
Value of E(x²)
E(x²) = summation {x²P(×)}
= summation{x²×1/n}
= 1/n
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Define x :
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Let the smallest number be x.
The other two numbers will be x + 1 and x + 2.
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Construct Equation :
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Sum of these numbers is 72
⇒ x + x + 1 + x + 2 = 72
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Solve for x :
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x + x + 1 + x + 2 = 72
3x + 3 = 72
3x = 69
x = 23
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Find the numbers :
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1st number = x = 23
2nd number = x + 1 = 23 + 1 = 24
3rd number = x + 2 = 23 + 2 = 25
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Answer : The numbers are 23, 24 and 25.
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You use elimination the get x=5 and then plug it in to get y=0 so the coordinate is (5,0)
15 times D= 300
the 15 is pages
D is pages per day
300 is amount of total pages
