The 36-year-old runner ran under 3:00:00 when almost 3:30:00 is expected. The 39-year-old runner ran slightly above 3:00:00 when 3:30:00 is expected. The 41-year-old runner ran slightly above 3:00:00 when about 3:45:00 was expected. Therefore, three runners ran at least 15 minutes faster than predicted, which matches (C). If you chose (B), you may have based your choice on the number of runners who ran more than 15 minutes slower than their predicted time.

According to the table, the relative investment in wind resources in 2007 was 0.40 of the total 1.00. Probability is defined by the number of things that fit the requirements divided by the total number of things. In this case, that would be ​\( \frac{0.40}{1.00} \)​. You don’t need to worry about the actual dollar values, because these numbers both relate to the same total of $75 million. You do, however, need to simplify this fraction. You can multiply it by ​\( \frac{10}{10} \)​to get ​\( \frac{4}{10} \)​, which then reduces to ​\( \frac{2}{5} \)​. You could also divide it on your calculator to get 0.4, and then divide each fraction in the answer choices to see which one is also equal to 0.4. Either way, the correct answer is (C).

Examine each answer choice and use Process of Elimination. For (A), the 2007 investment in biofuels was 0.31 out of 1.00, or about one-third of the total, according to the chart. The total that year was $75 million, so the Ballpark value would be about $25 million. The $50 million value in (A) is too high, so eliminate it. Choice (B) refers to percents, but the chart is in “relative” investment. If the 2007 relative investment in wind is 0.40 out of 1.00, it is equivalent to 40% of thetotal. The wind investment in 2017 is projected to be .32 or 32% of the total, which is a decrease of 8%. Check out (C) and (D) just to be certain. For fuel cells, the percent of the total is projected to double, but the total in 2017 is projected to be much higher. So the total dollar amount invested in wind in 2017 will be much more than double the 2007 investment. For (D), the top three energy types-biofuels. wind, and solar-are projected to be more equally invested in for 2017 than they were in 2007, so (D) is the opposite of what the chart shows. Eliminate (C) and (D), and choose (B).

Whenever there are variables in the question and in the answers, think Plugging In. If m = 10, then Monster Truck Inc., receives a down payment of $3,200 plus 10 months’ worth of monthly payments. This can be calculated as 3,200 + 10(380) = 3,200 + 3,800 = $7,000. Plug in 10 for m in the answers to see which function equals 7,000. Choice (A) becomes f(m) = 380 + 3,200(10) = 380 + 32,000 = 32,380. Eliminate (A). Choice (B) becomes f(m) = 3,200 + 36(10) = 3,200 + 360 = 3,560. Eliminate (B). Choice (C) becomes f(m) = 3,200 + 380(10) = 3,200 + 3,800 = 7,000. Keep (C), but check (D) just in case it also works. Choice (D) becomes f(m) = 10,480 – 380(10) = 10,480 – 3,800 = 6,680. Eliminate (D). The correct answer is (C).