The answer is B. (15,18)
Solution:
First, let's set the variables first.
X = dollars per hour to clean the floor
Y = dollars per hour to clean the rest of the house
For the first statement, "<span>2 hours to clean floors and 3 hours to clean the rest of a house, the total charge is $84"
We can put it into an equation.
2X + 3Y = 84 </span>⇒ equation 1
For the first statement, "<span>1 hour to clean floors and 4 hours to clean the rest of a house, the total charge is $87'
X + 4Y = 87 </span>⇒ equation 2
Multiply first equation 2 by 2 to make the coefficient of both equations 1 and 2 the same.
Using elimination method in solving for x and y,
(equation 1) 2X + 3Y = 84
(equation 2) 2(X + 4Y) = 87
2X + 8Y = 174 ⇒ equation 3
Next, subtract equation 3 from equation 1.
2X + 3Y = 84
- (2X + 8Y = 174)
-------------------------
- 5Y = -90
Y = 18
Find X when Y = 18
@ equation 1 : 2X + 3Y = 84
2X + 3(18) = 84
2X + 54 = 84
2X = 84 - 54
2X = 30
X = 15
The answer is in ordered pairs of cleaning the floors and to clean the rest of the house. So, in the form (X,Y).
Answer: (15,18)
Answer:
You can opt to study the entire population when the population is well defined(Complete sampling frame) and small.
It can eliminate any potential bias occurring through sampling technique, but other than that it is really not justified to consume more resources and time.
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