a question for everyone (do answer please)

if a bean can split itself into two every second
from 1 bean to 2 beans in the 1 sec
from 2 beans to 4 beans in the 2nd sec
from 4 beans to 8 beans in the 3rd sec

let say if the bean take 60 secs to multiply and fill a bag

how long will it need to fill the bag if the initial number of bean is 2 instead of 1?

come come come !!
shoot me your answer at tagboard :)