Question

suppose the amount of algae in a pond doubles every 3 hours if the pond initially contains 50 pounds of algae , how much algae will be in the pond after 9 hours

Answer 1

400 pounds because after the first three hours you have 100 pounds and after the second three hours you have 200 pounds now you're at 6 hours and than after the third three hours you have 400 pounds after 9 hours

Answer 2

50*2=100 100*2=200 200*2=400
So there would be 400 pounds off algae in 9 hours