We are given with the variable cost which is:
q = -20s + 400
The selling price is 's'. So, the profit can be represented by:
P = qs - q(12)
Subsituting:
P = (-20s + 400)s - 12 (-20s + 400)
P = -20s^2 + 640s - 4800
To optimize this, we must differentiate the equation and equate it to zero, so:\
dP/ds = -40s + 640 = 0
Solving for s,
s = 16
So, the selling price should be $16 to optimize the yearly profit.
The correct answer is 21 simply because 21 is a multiple of 3 and a multiple of 7, other answer does not hold this conclusion.
X would =18 because 18+2= 20
20 x .5 = 10
X = 18
One way is to make them all decimals or all fractions:
.5 .2 .35 .48 .80 are the numbers above changed to decimals.
I will make them the same length (two digit past the decimal point) to compare
.50 .20 .35 .48 and .80
Now it is easy to put them in order
.2 .35 .48 .5 and .80
Let's put them into all fractions
5/10 1/5 35/100 12/25 and 4/5
Instead of finding a common denominator let's try this:
Think of them as test scores - the person who got 1 out 5 did the worst
Next came the person who got only 35 out of 100 - they only did better than the one above (1/5)
12/25 is almost 1/2 but a little below half the questions right
5/10 is exactly half the questions right (so it is bigger than 12/25 by a little).
4/5 is the best score (and the only one who passed).
So 1/5, 35/100, 12/25, .5 and 4/5 are in order least to greatest and match the answer above in bold.
Answer:
is rational number.......
