Let us start with assuming the amount of coffee worth $20 a pound to be "x" pounds.
Now she wants to mix "x" pounds of $20 coffee with 70 pounds of $90 coffee.
So the mixture would be (x + 70) pounds.
And the value of mixture would be = 20·x + (90)·(70) = (20x + 6300) dollars.
She want to sell this mixture at rate of $30 a pound. Her earning would be = 30·(x + 70) = (30x + 2100) dollars.
We know that the value of mixture would be equal to her earnings.
30x + 2100 = 20x + 6300
30x - 20x = 6300 - 2100
10x = 4200
x = 420
So, 420 pounds of $20 coffee would be used.
Answer:
(-1,-1)
Step-by-step explanation:
Because that is where the dot is.
Hope this helps :)
<span>Diameter of a grain of sand = 2 x 10^{-4}
</span><span>Diameter of the average cell in the human body = 1 x 10^{-5}
</span>
Difference of diameter of grain of sand and cell of human body
= 2 x 10^{-4} - 1 x 10^{-5}
=

=

=

=

=

= 19 × 10^{-5}
Hence, the diameter of a grain of sand is
19 × 10^{-5} longer than the diameter of the average cell of the human body.