Ok guys, I will put you out of your misery!! I'm sure that some will debate this, so I will just stay out of it and let you guys debate among yourselves!! lol
Back to the dieter #1 and dieter #2 dilemma:
d1 lost 1/8 of his weight, or 19 lbs.
We say 1/8 = 19/x where x=d1's original weight.
So, you are correct when you solve:
(Cross multiplying, then dividing:) 19 * 8 = 152 --> 152/1=152 --> x=152
NOW...
d2 weighs 2 lbs more than 152, or 154, after losing 1/6 of her original weight. What was her original weight?
Let x= d2's original weight
We know that her weight loss equals her original weight minus 154, or x-154=weight loss
and we know that she lost 1/6 of her original weight, or x/6, SO x/6 also = weight loss
Now we have the equivalence: x-154 = x/6 (weight loss equals weight loss)
(There are a number of ways you can go from here, but here's one...)
Subtract x from each side --> -154=x/6 - x
Since we know that the quantity x also equal x/1, we put x in the form of a fraction to facilitate subtract of fractions on the right side of the equation:
-154=((x/6)-(x-1))
In order to simplify the right side, we can subtract to find the difference x/6-x/1. But first, of course, we must convet to like terms. Using 6 as a common denominator, we rewrite the right side to ((x/6)-(6x/6)).
We now have the equivalence of -154=((x/6)-(6x/6)) or -154= (-5x/6) (You have "x" sixths minus "6x" sixths = -5x sixths)
Multiplying both side by 6 yields -924=(-5x)
Dividing both sides by -5 yields x = 184.8 lbs
You can check this by calculating as you did for d1. 1/6=x/154 --> We think weight loss - 184.8-154 or 30.8lbs so 1/6=30.8/154 which is true.