Passage V

The higher a gasoline's octane number (ON), the more smoothly the gasoline burns, lessening engine damage. Sulfur (S), naturally present in gasoline, damages exhaust systems in cars. Table 1 gives the ON and S content of 6 gasolines (Fuels A-F).

Figures 1 and 2 show the decrease in ON resulting from using Methods 1 and 2, respectively, to reduce a gasoline's S content from a given initial value to a given final value. Consider a gasoline having an ON of 90.00 and an S content of 100 ppm. If Method 1 is used to reduce the S content to 25 ppm, Point A in Figure 1 shows that the decrease in ON will be 0.35, so the ON will decrease to 89. 65 (because 90.00 - 0.35 = 89.65).

28. Fuel A was formulated by using Method 2 to reduce the S content of another fuel, Fuel Z. Based on Table 1 and Figure 2, before Fuel A was formulated, if the S content of Fuel Z was 75 ppm, the ON of Fuel Z was approximately what value?

Answer and Explanation

Your Answer is

Correct Answer is J

Explanation

Understand the stem of the question carefully. The meaning in the stem of the question is probably fuel Z + method 2 = fuel A. Look at table 1 first, the ON of fuel A is 83, and the S content is 14;

Look again In figure 2, the curve with initial S content of 75 ppm, when the abscissa is 14, the ordinate is about 0.6, so the ON of fuel Z decreases by 0.6 and becomes the ON of fuel A, which is 83. So the ON of fuel Z should be equal to 83+0.6=83.6