Answer:
your answer is going to be 220.
You need one equation of this problem to balance the amount of a boric acid.
The amount of boric acid in 50% solution is expressed as 0.50*x
Next, the amount of water is taken from 25 liters and x (based on 50% solution), that is 25 - x. However, there is NO amount of BORIC ACID in water, and that is 0.
For the output solution, the amount of boric acid will be 0.10*2.5 = 2.5
Then, the balance equation is
0.50*x + 0*(25 - x) = 2.5
Solving for x,
0.50*x + 0 = 2.5
x = 2.5/0.5 = 5
Therefore the amount of liters in 50% solution is
5*0.50 = 2.5 liters
The amount of water is 25 - 5 = 20 liters
We know, cos A + cos B = 2cos(C+D)/2 × cos(C - D)/2
So,
cos 130 + cos 110 + cos 10
cos 130 + 2cos (110+10)/2 × cos( 110-10)/2
cos 130 + 2cos 60 × cos 50
cos ( 180 - 50 ) + 2cos60 cos 50
We know, cos ( 180 - A ) = -cos A
2cos 60 cos 50 - cos 50
Also, cos 60 = 0.5
2×0.5 cos 50 - cos50
cos 50 - cos 50
0 = RHS.
Hence proved
Since opposite exterior angles are congruent I would plug in numbers for X till you find a number that goes into both and gets you the same product.
