We read these words:

"...15 OUT OF 35 ON HER TEST..." 

 That's comparing 15 to 35.  


Then we ask ourselves: "Comparing 15 to 35 is like comparing what to 100?"

Here's what you do.  You translate the first three words "Comparing 15 to 35"
(I call numbers words).  Their translation is "make the fraction ".

Translate the next three words: "is like".  That's just an = sign, so put
an = after the  and you now have 

Now we come to this: 

WHAT PERCENT DID HE GET CORRECT?
 
x is the "what".  That translates like the first "comparing 15 to 35" except
we're now "comparing x to 100" like we compared 15 to 35. So we make the
fraction "" and put that on the other side of the = sign. 

Now we have the equation:

 

We solve that by cross-multiplying

35x = 1500
  x = 
  x = 43% rounding off from what the calculator gave me to a whole percent. 
    
So 15 compares to 35 just like 43 compares to 100.

(Rounded to tenths it was 42.9%)

She FLUNKED! TOO BAD!  She should haved studied more. 

Edwin