http://sat.collegeboard.org/practice/sat-question-of-the-day?src=R&questionId=20130209 (This link takes you to today’s question. If you use my archive, you will see the question related to my SAT explanation for that date.)
The answer is E. Yeah, I get it but the SAT explanation is a little hard to follow. They want you to mess with the algebra and it can get a little confusing when you are in a hurry on test day. There’s a much easier way to do this and similar questions when they don’t give you numbers. My students will tell you I call this “change the abstract to the concrete” or “change the algebra to arithmetic” or “change the variable to numbers” or … Well, you get it by now. Forget the c and g and make stuff up by substituting you own numbers. Be gentle–use easy numbers. Let’s say that there are 10 cars, not c. Let’s say they use 50 gallons, not g.
So, if there are 5 of 10 cars you know that is half because 5/10 represents the fraction of the cars and you know that you have to double the weeks since there are two weeks, that would be 100 gallons. So 1/2 of 100 is 50. That means that the answer has to to be 50 when g=50 and c=10. That’s right, I don’t have c and g anymore. I just substitute 50 and 10 in the answers for c and g which changes the abstract/algebra to the concrete/arithmetic. When you do that, E is the right answer: 10g/c=10(50)/10=50. There is more about this strategy in my online course and on DVD #4. The most important issue is that you practice this technique. Since there a lot of questions that give you variables instead of numbers on both the SAT and ACT, you should master it. It will save you time and help you get more questions right when you are in a hurry on test day. You can’t beat that!
Most importantly, it doesn’t matter what numbers you substitute for c and g. As long as you plug them in the answers, they work. Why? Because “the world of math is a world of patterns.” That is one of my favorite principles about math and it can be used numerous times on the SAT and ACT to answer questions quickly and accurately. Go ahead, try your own numbers for c and g; you’ll see that it works.
I wonder what the ACT test writers have prepared for us this snowy morning for those of you in New England. Just to make you jealous, it’s 59 and headed for 78 where I live! Come on down!!
http://www.act.org/qotd/ (The ACT staff does not put a date on their questions so if you click on an archived blog, you’ll get today’s question and the old explanation. Sorry. The SAT staff has dated their questions; so, the archive is helpful. The ACT folks simply don’t do that.)
The answer is D. This is a perfect example of my contention that most of the questions are about whether you can read charts and graphs rather than whether you know any science. They tell you the science; so, all you have to do is understand how scientists develop and record data. They tell you the in the introductory paragraph that the stick is 1 meter tall. The tell you in the question that the shadow has to be as long as the stick. Well, duh, then the shadow has to be 1 meter long. They tell you in Table 2 on Day 3 that the shadow is 1 meter long, answer D. Take a deep breath, relax and go on to the next question.
I hope you find lots of questions this easy this morning if you are on your way to taking the ACT!
I am finding it very gratifying that teachers are using my blog as part of their instruction. I had two teachers in NC sign up yesterday (Welcome!) and I even have a university professor using my materials in his classroom in OK. If you think your friends at school would benefit from these explanations tell them and your teachers. Have your school add my blog to the list of resources they have on your school’s website for test prep. The SAT and ACT Questions of the Day and my explanations will help you and your classmates not only for the test but also in school and when you get to college. Can you say, “Facebook?” Enjoy!