Answer:
The smallest possible beat frequency when B and C are sounded together is 3 Hz
Step-by-step explanation:
Given;
the beat frequency of A and B = 2 Hz
the beat frequency of A and C = 5 Hz
Beat frequency is equal to the difference in frequency of the two notes that interfere to produce the beats.
![F_b_((AB)) = 2 \ Hz\\\\F_A - F_B = 2 \ Hz -----equation(1)\\\\F_b_((AC)) = 5 \ Hz\\\\F_A - F_C = 5 \ Hz-----equation(2)\\\\from \ equation(1), make \ F_A \ the \ subject \ of \ the \ formula\\\\F_A = 2H_z + F_B -----equation (3)\\\\Substitute \ in \ the \ value \ of \ F_A \ in \ equation(3) \ into \ equation(2)\\\\2H_z + F_B - F_C = 5H_z\\\\F_B-F_C = 5H_z - 2H_z\\\\F_B -F_C = 3Hz](https://img.qammunity.org/2021/formulas/physics/college/evne4nv2xwec2gibxiqdklbn0e4y5stgge.png)
Therefore, the smallest possible beat frequency when B and C are sounded together is 3 Hz