Simplify the expression: 15(ab^2)^3 / (a^4b^6), where a = 3 and b = 1.22

1. Simplify the numerator: 15 * a^3 * b^6. 2. Simplify the expression: 15 * a^3 * b^6 / (a^4 * b^6) = 15 / a. 3. Substitute a = 3: 15 / 3 = 5.