A rare bacterial culture is being grown in a lab. As time passes, the cells multiply in a specific pattern. After 1 day, there is only 1 cell.
After 2 days, there are 8 cells.
After 3 days, there are 18 cells.
After 4 days, there are 31 cells.
How many cells will there be after seven days? (2 points)
66
O a
Ob
88
110
Od
113

Can some one me with these questions

Two airplanes start at the same place and travel in opposite directions,one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?