Let x represent the amount to be added. The total amount of tin will be
15%·20 + 10%·x = 12%·(20+x)
(15%-12%)·20 = (12%-10%)·x
3%·20/2% = x
30 = x
30 pounds of 10% tin must be added to get a 12% mixture.
Answer:
Step-by-step explanation:
............................................ (1)
............................................ (2)
now equate both (1) and (2)
now substitute the values of x ,
when 
, y becomes 0
when 
, y becomes 8
so, solution set:
and 
A) x=4
B) x= -3
C) x= -1/6
D) x=24
6.808 is the correct answer
Hope this helped you
Remember, rise/run is the easiest way to determine slope
y=mx+b is form
mx is slope, whilst b is y int
so, answer? y=-3x-2
Or A.
