In a recent flu epidemic, the number of flu cases increased by 40% each week. there were 3,000 flu cases during the first week of january. how many more people were affected by the flu during the third week of january than during the first week?

Given:
1st week = 3,000
rate of increase = 40% each week.

1st week = 3,000
2nd week = 3,000 x 1.40 = 4,200
3rd week = 4,200 x 1.40 = 5,880

5,880 - 3,000 = 2,880 

There were 2,880 people more that were affected by the flu during the 3rd week as compared to the 1st week.

1.40 is used as multiplier instead of 40% because we still have to add the 40% to its original number to get the new total number.

3,000 x 0.40 = 1,200 
3,000 + 1,200 = 4,200   *same answer if we multiply 3k by 1.40