Chains, Ropes, and Slings Test I Source: Questions and answers from the National Safety Council Progress Indicator: Question 4 of 20 4.  A MINE ENTRY IS 5 FEET HIGH AND 17 FEET WIDE, THE READING ON THE ANEMOMETER IS 300 FPM FOR 1 MINUTE, WHAT IS THE QUANTITY OF AIR? Choices: 25,500 cfm 26,500 cfm 27,500 cfm 28,500 cfm