So, how much acid is there in 6 gallons? well is 20% acid or (20/100), so the amount of acid in it just (20/100) * 6 or 1.2, the rest is say water.
now, if we want a 90% solution, and say we add "y" gallons, how much acid is in it? well (90/100) * y, or 0.9y.
now let's add "x" gallons of pure acid, now, pure acid is just pure acid, so is 100% acid, how much acid is there in it? (100/100) * x, or 1x or just x.
we know whatever "x" and "y" amounts are, they -> x + 6 = y
and we also know that x + 1.2 = 0.9y
A) 1/3=33 1/3%
B) 2/3=66 2/3%
C) 1/6=16 2/3%
A) YOU CAN TURN THE FRACTION 1/3 INTO A DECIMAL WHICH WILL BE AROUND 0.333. THEN YOU TURN THE DECIMAL INTO A PERCENT. YOU CAN MOVE THE DECIMAL TWO PLACES TO THE RIGHT. THAT GIVES YOU 33.3% OR 33 1/3% THIS ALSO APPLIES TO B BUT WITH 0.666 AND 66.6%
FOR C, YOU DO THE SAME. 1/6 AS A DECIMAL IS 1.666. YOU MOVE THE DECIMAL TWO PLACES TO THE RIGHT. 16.6% OR 16 2/3%
HOPE THIS HELPED.
$15 x .0725 = 1.0875 which we have to round to $1.09
Notice how I changed the 7.25% to a decimal .0725 by moving it back two places.
Write out the slope formula:
m = (change in y) / (change in x)
Here,
m = n-(-9) / (-6-(-2)) = (n+9 / (-4)
Now set this slope equal to -1 and solve the resulting equation for n:
(n+9) / (-4) = - 1, or (n+9) / 4 = 1, or n+9 = 4. Then n = -5.
1/10
hope this helps u out!