50 ounces of 15% saline solution contains 0.15*50 = 7.5 ounces of salt.
Let x be the amount of pure water you add to this solution. Then you end up with (x + 50) ounces of this new solution. The amount of salt stays the same.
You want the new solution to have a concentration of 10%. This means you need
7.5 / (x + 50) = 0.1
==> 7.5 = 0.1(x + 50)
==> 7.5 = 0.1x + 5
==> 2.5 = 0.1x
==> 2.5/0.1 = 0.1x/0.1
==> x = 25
Step-by-step explanation:
-7(y-1)= 21
-7y+7=21
-7y=21-7
-7y=14
divide by-7
y=-2
D is the answer that is graphed.
He sold 12 coins, 16+28+32+4=80. 15% of 80 is 12
The answer for that one is B, because 26<54
meaning 26 is less than 54 which is true