This question is from my calculus class and I am not sure how to do it

1. Suppose that for a certain leaf-cutter ant colony, the birth rate is modelled by: B(t) = 23, 000 - 80 sin ants per day and the death rate is modelled by: D(t) = 21, 000 - 30 cos(3xt) ants per day. (a) Compute 30 (B(t) - D(t)) at and briefly explain what this quantity represents in terms of the colony. (b) Compute the average number of ants born per day, in the time from t = 10 days to t = 40 days. (c) Suppose that at time t = 0, there are 739,000 ants in the colony. According to the model, how many ants are in the colony at time t = 31