**Problem:**

Modelers have estimated that in the AM peak hour, the number of trip origins (To) is a function of the number of households (H) and the number of jobs (J), and the number of trip destinations (Td) is also a function of the number of households and number of jobs.

Suburbia: 30000 H, 5000 J

Urbia: 6000 H, 29000 J

1) Determine the number of trips originating in and destined for Suburbia and for Urbia according to the model.

2) Does this result make sense? Normalize the result to improve its accuracy and sensibility?

3) If the interzonal travel cost (from Suburbia to Urbia or Urbia to Suburbia) is 10 minutes, and the intrazonal travel cost (trips within Suburbia or within Urbia) is 5 minutes, use a (doubly-constrained) gravity model wherein the impedance is f(tij) = 1/t2ij, calculate the impedance, balance the matrix to match trip generation, and determine the trip table (within 2 percent accuracy).