IN 1991 Northwest Airlines operating revenues were $7500 million. This is 82% of Delta AirLines operating revenue in 1991. What were Delta Air Lines' operating revenues in 1991? Round to nearest million.

82% is 82/100 or 0.82.
Multiply as usual.

No - divide Northwests's revenues by 0.82. Delta's revenues were greater than Northwest's.

7500 divided by 100 and times by 82