Think of it as 0 times 0 times 0
Answer:
8 hours
$480
Step-by-step explanation:
Let us assume the hours be x
There should be two equations
For Plumber A = 60x
For Plumber B = 40 + 55x
Now in order to considered the cost to be the same we equate these two equations
60x = 40 + 55x
5x = 40
x = 8 hours
Now the total cost for plumber A is
= 480
And, the total cost for plumber B is
= 40 + 55(8)
= 480
hence, the total cost is $480
Answer:
Step-by-step explanation:
Given that 30% of all students who have to buy a text for a particular course want a new copy (the successes!), whereas the other 70% want a used copy.
Each purchaser is independent of the other and there are only two outcomes
X - no of persons who prefer new copies is Bin (15, 0.3)
a) E(x) = np =
Var(x) = npq =
Std dev (x) = 1.775
b)
c)
d) h(X) = revenue when x of 15 purchasers want new copies
E(h(x)) = 100(E(x) = 450
Here h(x) = 100x
Hence E(100x) = 100E(X)
Let x be the cost of each book.
So, the cost of 4 books is 4x.
For the purchase of 4 books, he got a discount of $20.
So, the amount he paid for the first four books = 4x - 20.
Now, the cost of 5 books is 5x.
For the purchase of 5 books, he got another discount of $5.
So, the amount he paid for the five books = 5x - 5.
Total money spent = $87.
Therefore, (4x - 20) + (5x - 5) = 87
4x + 5x - 20 - 5 = 87
9x - 25 = 87
9x = 87 + 25
9x = 112
Divide both sides by 9.
x = 12.4
Hence, the cost of each book = $12.4.
Explanation is in the file
tinyurl.com/wpazsebu