Answer :
4000 frequent flyer miles did David have last month.
Given that,
Together, David and Carol have a total of 35,000 frequent flyer miles with an airline.
Carol has 19,000 miles.
After going on a business trip, David has 1200 more miles than he had last month.
We have to determine,
How many frequent flyer miles did David have last month.
According to the question,
David and Carol have a total of 35,000 frequent flyer miles with an airline.
Carol has 19,000 miles.
= 35,000 - 1900 = 16,000
After going on a business trip, David has 1200 more miles than he had last month.
Then,
David have last month frequent flyer miles is,
= 16,000 - 12,000 = 4,000
Hence, 4000 frequent flyer miles did David have last month.
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