http://sat.collegeboard.org/practice/sat-question-of-the-day?src=R&questionId=20121231

This SAT question is not so bad; it’s completely consistent with what you should expect on the test. You will find this error on my list of common grammar mistakes that are found on the test. Even better, I tell you how to find them. Check out my SAT and ACT test prep class no matter whether it is live, on DVD, or here on the website.

For example, in this case a pronoun is underlined (B) and you should immediately check its antecedent. *Its* refers to the *scientists.* Since *its* is singular and *scientists* is plural, you’ve found the mistake; circle B in the test booklet and bubble it in. You are ready to move on.

Why circle it in the test booklet? Well, if you screw up the bubble sheet, it’s very easy to fix everything since you have a record of your answer in the test booklet!

Let’s move on to see what the ACT folks have in store for us this fine New Year’s Eve morning.

Gosh, their computers must have a hiccup! This question was just on the QotD. I initially thought I was in a time warp until I saw today’s date at the top of the ACT question. H.G. Wells is safe! Maybe the ACT test writers are taking a day off and just didn’t want to find a different question. I got it–they started celebrating early and then picked the question. Think about it! Wouldn’t you think they would have found an older question? Surely there’s one in their test bank from last year!

The answer is J. Here’s my explanation from December 27th!

Not bad if you are careful with the signs (+/-). It’s quickest and easiest if you subtract 6 from both sides of the equation and then you only have to worry about x^{2 }– 7x= 0.

It’s easy enough to see that plugging in 0 for x will solve the equation since 0 times anything is 0. Now the only issue is does one of the negative answers work. -6 and -4 are silly since x-squared has to involve 7 in order for -7x to get us to 0. Plugging in -7 gives us 49 for x-squared. However, when you subtract (7 times -7), you are subtracting -49 which is a plus! 49 + 49 isn’t 0.

You can think your way to this answer very quickly. Of course, you can do the algebra as it is explained by the ACT folks on their website.

Be sure to do a free registration for my website and I’ll email you the explanation every day.

I hope you find my quick tricks for math helpful. If so, let your friends know about my blog. You’ll find all of my tips and tricks in my ACT and SAT programs. Hopefully, I’ll see you in class or on the Internet.

Happy New Year

The Wizard