Here’s the correct answer and how I got it :)
The easiest way is to try the point (-4,1), that is, x=-4, y=1,
to see which equation works.
b works.
The usual way to do it is to find the equation of the circle
standard form of a circle is (x-h)²+(y-k)²=r², (h,k) are the coordinates of the center, r is the radius.
in this case, the center is (-2,1), so (x+2)²+(y-1)²=r²
the given point (-4,1) is for you to find r: (-4+2)²+(1-1)²=r², r=2
so the equation is (x+2)²+(y-1)²=2²
expand it: x²+4x+4+y²-2y+1=4
x²+y²+4x-2y+1=0, which is answer b.
Let us take the case of first type of tea
Cost of 10 kg of tea one = $20
Then
Cost of 1 kg of tea one = (20/10) dollars
= 2 dollars
Now let us take the case of the second kind of tea
Cost of 10 kg of tea = $23
Then
Cost of 1 kg of tea = (23/10) dollars
= 2.3 dollars
So
The mixture of 1 kg of tea one
and 1 kg of second type of tea will cost = (2.0 + 2.3) dollars
= 4.3 dollars
Then the cost of 2kg mixture of tea costs = 4.3 dollars
So
The cost of 10 kg mixture will cost = (4.3/2) * 10 dollars
= 4.3 * 5 dollars
= 21.5 dollars
Then
The amount of profit made by selling 10 kg tea at $38 = (38 - 21.5) dollars
= 16.5 dollars
So
Percentage of profit made = (16.5/21.5) * 100
= 1650/21.5
= 76.74 percent
So the percentage of profit made is 76.74%.
