Answer:
She consumes 30 blue ray disk and 60 DVD respectively.
Step-by-step explanation:
Consider the provided information.

Calculate marginal utility of good
Differentiate with respect of x and y.


Her consumption of Blu-ray disks (X) with a price of $40 and Y is her consumption of DVDs with a price of $10.
The ratio of marginal utility of good x to y is equal to the price ratio:

Substitute the respective values.




She has $1800 with which to spend on the two goods.
Her consumption of Blu-ray disks (X) with a price of $40 and Y is her consumption of DVDs with a price of $10. She has $1800 with which to spend on the two goods.
Therefore, 

Substitute the value of y in above equation.



Thus, 
She consumes 30 blue ray disk and 60 DVD respectively.
The elevations of four points below sea level are -47 feet, -24 feet, -8 feet, and -18 feet.
The elevation of the point closest to sea level is feet
-8 ft
elevation of the point farthest from sea level is feet.
-47 ft
closet to sea level to farthest to sea level
-8ft , -18ft , -24ft , -47ft
Answer:
Step-by-step explanation:
If
72 cents ---> 6 ounces
Xcents -----> 8 ounces
then
X = [(72)*(8)] / 6
X = 96 cents
Best regards
First, isolate y in 7x-y=29 because 1 is y's coefficient.
7x-y=29
-y=29-7x
y=7x-29
Now, substitute 7x-29 for y in 7x+8y=20.
7x+8y=20
7x+8(7x-29)=20
7x+56x-232=20
Add all coefficients.
63x-232=20
Isolate x by adding 232 to both sides.
63x-232=20
63x=252
x=4
Now, substitute 4 for x in your first equation.
y=7x-29
y=7(4)-29
y=28-29
y=-1
Your answer would be (4,-1).
Any questions you may have, please contact me or comment.