Plz help plz ill give brainliest A scientist is growing bacteria.

The number of bacterial cells triples every week.
There are currently 20 cells.

Which expression shows how to find the number of cells in 4 weeks?
A. f (4) = 3 ∙ 204
B. f (4) = 4 ∙ 203
C. f (4) = 20 ∙ 34
D. f (4) = 20 ∙ 43

David and alton are training for a race. they spend 35 minutes stretching and then go on a 5 mile practice run. david runs at a pace of 7 min/mile. alton runs at a pace of 8 min/mile. write an equation for each runner that shows the total length of their workout. then solve each equation showing your work