so, we need to find the relation between hours and the number of bacteria
Let the relation is
an = m n + d
Where m and d are constants
When n = 1 , an = 19
19 = m + d eq.(1)
When n = 2 , an = 38
38 = 2m + d eq.(2)
Solve the equations (1) and (2)
subtract (1) from (2)
38 - 19 = 2m + d - ( m + d )
19 = 2m + d - m - d
19 = m
Substitute with the value of m at equation (1)
19 = 19 + d
d = 19 - 19 = 0
So, the relation will be
an = 19 n
we can check the relation
The answer is option D. an = 19 n
