Why didn't I get this SAT Math question right? Help?

xiggi
Wed, 29 Aug 2012 17:03:08 +0000

“So what’s wrong with what I did?”

Used a 9 instead of 6.

The wrong entry in your work is 21(9) = 189 … It should have been 21(6) or 126. And 28(12) should have been 28(9) or 252.

126/252 = 1/2.

PS This shows your errors, but smaller entered values would have worked better.