JNU SSS 2014 Question 37: Keynesian cross and the multiplier

Suppose in an economy in any period $t$ the aggregate value of output is $Y(t) = C(t) + I(t)$, the sum of aggregate consumption and investment expenditures.

Suppose $C(t) = 0{\cdot}6Y(t) + 0{\cdot}3Y(t - 1)$ and $I(t) = 600 + 0{\cdot}1Y(t)$ for all $t$ and $Y(0) = 40000$. What is the rate of growth of output in the economy in period 1?