How to solve exponential growth

on a particular day 27 cases of the influeza virus were reported to health authorities, 7days later 435 cases were reported.

assuming that the growth in the number of cases is exponential, how many cases will they expect by the end of the next 7 days?

please help i dont even know how to start the question.

simpler way
=========
unless use of "e" is compulsory, base ans on the general exponential formula
y = ab^x
in 7 days, the cases increase to (435/27) = (145/9) fold, so
in another 7 days, it will increase another (145/9) fold
y = 27*(145/9)^(14/7) = 7008 <-------

N = A e^(kt)

From the initial conditions :

N = number after t days ; N = 435 ; t = 7 days ;
A = initial number ; A = 27
k = constant

k = (1/7) ln 435/27 ≈ 0.397

Then at t = 14 days ,

N = 27 e^( 0.397*14) = 7001 ( or , if you use the exact value for k , 7008 )