C) Tw = D) Tw = Cut the Fat
Word problems on the SAT
often contain unnecessary
information. If you find the
unnecessary information
distracting, you can lightly
strike through it. In this
question, the explanation
of the variables is not nec-
essary, so you can cross
out everything after the
equation to “...the water
is exposed to sunlight”
without removing any
information necessary to
answering the question.Here’s How to Crack It
The goal is to get Tw by itself. Anything you do to one side of the equation, you must also do to the other
side of the equation. Start by multiplying both sides by h^4 to get rid of the denominator on the right side of
the equation.
The equation becomes
Eh^4 = To get the fraction with Tw alone on the right side, subtract the other fraction from both sides to get
Eh^4 − Multiply both sides by Tw to get that variable out of the denominator.
= −V
Now divide the whole expression by the entire thing inside the parentheses.
Tw = −