A culture started with 2000 bacteria. after 8 hours it grew to 2400 predict how many bacteria will be present after 19 hours?

This is a geometric sequence but you don't know the growth factor, so you would solve for it first.

2400 = 2000 (x) ^8

1.2 = x^8

x = 1.02305188

You can round depending on what your teacher prefers.

Now you can plug in your growth factor and solve.

A (19) = 2000 (1.02305188) ^19

A (19) = 2000 (1.54189747739)

A (19) = 3083.79495477

After 19 hours, 3,084 bacteria will be present.