A pipe invert drops 2.4 ft over 160 ft. What is the slope percentage?
Correct Answer
B) 1.5%
Slope is 2.4 / 160 x 100 = 1.5%.
Why This Is the Correct Answer
Slope is 2.4 / 160 x 100 = 1.5%.
Why the Other Options Are Wrong
Option A: 0.7%
slope percentage, choice a: 0.7% implies about 0.44 percent fall over 160 ft; the stated slope is the one used in Slope is 2.4 / 160 x 100 = 1.5%.
Option C: 2.4%
slope percentage, choice b: 2.4% is wrong because 2.4% implies about 1.5 percent fall over 160 ft; the stated slope is the one used in Slope is 2.4 / 160 x 100 = 1.5%.
Option D: 15%
slope percentage, choice d: 15% implies about 9.38 percent fall over 160 ft; the stated slope is the one used in Slope is 2.4 / 160 x 100 = 1.5%.
Memory Technique
Say the slope percentage rule aloud as a chain; the chain ends at 1.5%, not an intermediate stop.
Reference Hint
Open Pipe and Excavation Contracting, 2011; use by topic index - gravity drainage slope / pipe fall to confirm that Slope is 2.4 / 160 x 100 = 1.5%.
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