Final answer:
The population in Math Valley in 1965 was approximately 31,290.
Step-by-step explanation:
To find the population in 1965, we need to calculate the population growth from 1965 to 1990. We can use the formula A = P(1+r)^n, where A is the final population, P is the initial population, r is the growth rate per year, and n is the number of years. Substituting the given values into the formula, we have A = 15,000(1.024)^25. Calculating this, we find that the population in 1965 was approximately 31,290.