As depicted in the figure, a block of mass 10 kg is suspended via...

Since the spring balances are light, their masses are considered negligible.

A spring balance measures the tension force acting on it.

For the lower spring balance, the tension $T_2$ is equal to the weight of the $10\text{ kg}$ block. Thus, $T_2 = 10g$, and its reading is $10\text{ kg}$.

For the upper spring balance, the tension $T_1$ must balance the total downward force, which is the tension from the lower spring balance plus the weight of the lower spring balance.

Since the lower spring balance is massless, $T_1 = T_2 = 10g$.

Therefore, the upper spring balance also reads $10\text{ kg}$.

Both scales will display a reading of $10\text{ kg}$.