Answer: The first equation should be multiplied by 9 and the second equation by −4, to eliminate the y-terms and solve for x in the fewest steps.
Step-by-step explanation:
Given : Equation (1) 5x − 4y = 28
Equation (2) 3x - 9y = 30
to eliminate the y-terms and solve for x in the fewest steps, we should multiply equation (1) by 9 and equation (2) by -4 such that
9(5x − 4y) =9 (28)⇒45x-36y=252
-4(3x - 9y) = -4(30)⇒ -12x+36y= -120
Now adding both equations, y-term eliminated and we get, 45x-12x=132
⇒33x=132⇒x=4.
Answer:
6 2/3 mL
Step-by-step explanation:
Multiply thru by 100 to get:
1000 + 60x = 30*40 + 30x
30x = 200
x = 6 2/3 mL (amt. of 60% solution needed in the mixture)
Answer:
3.64 Km.
Step-by-step explanation:
Given,
Total population = 20,000 people
Population density = 480 people per square kilometer
Area of the circle town
Radius of the circle town
Hence, the radius of circle town is equal to 3.64 Km.
Complete question:
Dr. Lyte wishes to study speed of Reaction Time to press a button in response to the onset of a lamp. The independent variable (V) is the color of the light produced by the lamp (red, orange, yellow, green, or blue) Since only 10 participants are available, she elects to administer the IV within-subjects with all 10 participants being exposed to all five levels of the color variable. The order of the color of the light presentation is to be counterbalanced. Using concepts from the textbook, why would Dr. Lyte need to use counterbalancing in this scenario?
Answer:
Here,
Independent variable (IV) is: the color of the light produced by the lamp (red, orange, yellow, green, or blue)
We are also told only 10 participants are available.
All 10 participants are being exposed to all five levels of the color variable in the same order.
Counterbalancing is said to be a technique used when establishing task order. It helps prevent introduction if cofounding variables.
Dr. Lyte will need to use counterbalancing technique in this scenario because some of the participants may be unable to understand difference in similar colours. Example some participants may not be able to differentiate between orange and red when the red colour comes after orange.
But using counterbalancing technique, Dr. Lyte can avoid such an error.
